title: The parameters 'group' for goal org.codehaus.mojo:rpm-maven-plugin:2.1.5:rpm are missing or invalid
body: <p>When running </p>
  
  <pre><code>mvn clean rpm:rpm 
  </code></pre>
  
  <p>I get this error : The parameters 'group' for goal org.codehaus.mojo:rpm-maven-plugin:2.1.5:rpm are missing or invalid</p>
  
  <p>My parent pom.xml :</p>
  
  <pre><code>&lt;project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"&gt;
  &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
  &lt;groupId&gt;net.brewspberry&lt;/groupId&gt;
  &lt;artifactId&gt;brewspberry-rpm-parent&lt;/artifactId&gt;
  &lt;version&gt;0.1.0-SNAPSHOT&lt;/version&gt;
  &lt;name&gt;brewspberry-rpm-parent&lt;/name&gt;
  &lt;description&gt;brewspberry-rpm-parent&lt;/description&gt;
  &lt;packaging&gt;pom&lt;/packaging&gt;
  
  &lt;properties&gt;
      &lt;rpm.install.basedir&gt;/opt/tomcat&lt;/rpm.install.basedir&gt;
      &lt;rpm.install.webapps&gt;${rpm.install.basedir}/webapps&lt;/rpm.install.webapps&gt;
      &lt;rpm.install.config&gt;${rpm.install.basedir}/lib&lt;/rpm.install.config&gt;
      &lt;project.build.sourceEncoding&gt;UTF-8&lt;/project.build.sourceEncoding&gt;
      &lt;project.build.group&gt;Internet&lt;/project.build.group&gt;
  &lt;/properties&gt;
  
  &lt;modules&gt;
      &lt;module&gt;brewspberry-regulator-algo&lt;/module&gt;
      &lt;module&gt;brewspberry-api&lt;/module&gt;
      &lt;module&gt;brewspberry-core&lt;/module&gt;
      &lt;module&gt;brewspberry-jbatches&lt;/module&gt;
      &lt;module&gt;brewspberry-webapp&lt;/module&gt;
  &lt;/modules&gt;
  &lt;profiles&gt;
      &lt;profile&gt;
          &lt;id&gt;rpm-build&lt;/id&gt;
          &lt;activation&gt;
              &lt;property&gt;
                  &lt;name&gt;build-rpm&lt;/name&gt;
              &lt;/property&gt;
          &lt;/activation&gt;
  
          &lt;build&gt;
              &lt;plugins&gt;
                  &lt;plugin&gt;
                      &lt;groupId&gt;org.codehaus.mojo&lt;/groupId&gt;
                      &lt;artifactId&gt;rpm-maven-plugin&lt;/artifactId&gt;
                      &lt;version&gt;2.1&lt;/version&gt;
                      &lt;extensions&gt;true&lt;/extensions&gt;
  
                      &lt;executions&gt;
                          &lt;execution&gt;
                              &lt;goals&gt;
                                  &lt;goal&gt;rpm&lt;/goal&gt;
                              &lt;/goals&gt;
                              &lt;configuration&gt;
                                  &lt;classifier&gt;${rpm.classifier}&lt;/classifier&gt;
                                  &lt;copyright&gt;Biologeek&lt;/copyright&gt;
                                  &lt;icon&gt;src/main/resources/img/icon.png&lt;/icon&gt;
                                  &lt;distribution&gt;Brewspberry&lt;/distribution&gt;
                                  &lt;targetOS&gt;linux&lt;/targetOS&gt;
                                  &lt;needarch&gt;noarch&lt;/needarch&gt;
                                  &lt;group&gt;Internet&lt;/group&gt;
                                  &lt;packager&gt;${user.name}&lt;/packager&gt;
                                  &lt;changelogFile&gt;CHANGELOG&lt;/changelogFile&gt;
                                  &lt;defaultDirmode&gt;540&lt;/defaultDirmode&gt;
                                  &lt;defaultFilemode&gt;440&lt;/defaultFilemode&gt;
                                  &lt;defaultUsername&gt;tomcat&lt;/defaultUsername&gt;
                                  &lt;defaultGroupname&gt;tomcat&lt;/defaultGroupname&gt;
  
                                  &lt;properties&gt;
                                      &lt;project.build.sourceEncoding&gt;utf-8&lt;/project.build.sourceEncoding&gt;
                                      &lt;project.build.group&gt;net.brewspberry&lt;/project.build.group&gt;
                                  &lt;/properties&gt;
  
                                  &lt;requires&gt;
                                      &lt;require&gt;apache-tomcat &amp;gt;= 8.0.24&lt;/require&gt;
                                  &lt;/requires&gt;
                                  &lt;mappings&gt;
                                      &lt;mapping&gt;
                                          &lt;directory&gt;${rpm.install.webapps}/brewspberry-api&lt;/directory&gt;
                                          &lt;sources&gt;
                                              &lt;source&gt;
                                                  &lt;location&gt;./brewspberry-api/target/brewspberry-api/target/brewspberry-api-0.1.0-SNAPSHOT.war&lt;/location&gt;
                                              &lt;/source&gt;
                                          &lt;/sources&gt;
                                      &lt;/mapping&gt;
  
                                      &lt;mapping&gt;
                                          &lt;directory&gt;${rpm.install.webapps}/brewspberry-webapp&lt;/directory&gt;
                                          &lt;sources&gt;
                                              &lt;source&gt;
                                                  &lt;location&gt;./brewspberry-webapp/target/brewspberry-webapp/target/brewspberry-api-0.1.0-SNAPSHOT.war&lt;/location&gt;
                                              &lt;/source&gt;
  
                                          &lt;/sources&gt;
                                      &lt;/mapping&gt;
                                  &lt;/mappings&gt;
                                  &lt;postinstallScriptlet&gt;
                                      &lt;scriptFile&gt;
                                          src/main/resources/rpm/postinstall.sh
                                      &lt;/scriptFile&gt;
                                      &lt;fileEncoding&gt;utf-8&lt;/fileEncoding&gt;
                                  &lt;/postinstallScriptlet&gt;
                              &lt;/configuration&gt;
                          &lt;/execution&gt;
                      &lt;/executions&gt;
                  &lt;/plugin&gt;
              &lt;/plugins&gt;
          &lt;/build&gt;
  
      &lt;/profile&gt;
  &lt;/profiles&gt;
  </code></pre>
  
  <p></p>
  
  <p>I tried to modify it by adding or removing project.build.group but still does not work.</p>
  
  <p>I always get this error.</p>
  
  <p>Found several topics about 'sourceEncoding' missing or invalid issue but nothing about 'group' missing or invalid error.</p>