title: Default value for application.properties (profile) environment placeholder cannot be comma separated
body: <p>I have the following property in my application.properties.</p>
  
  <pre><code>spring.profiles.active=dev,local
  </code></pre>
  
  <p>This works fine. However, I decided to also expose this as an environment variable and keep <code>dev,local</code> as the default values. However the following does not work.</p>
  
  <pre><code>spring.profiles.active=${PROFILES_ACTIVE:dev,local}
  </code></pre>
  
  <p>It seems comma causes this issue.</p>
  
  <p>Checking the logs</p>
  
  <pre><code>[2018-05-24 05:38:28.163] [main] [INFO] [Application] The following profiles are active: ${PROFILES_ACTIVE:dev,local}
  </code></pre>
  
  <p>However, the following works.</p>
  
  <pre><code>spring.profiles.active=${PROFILES_ACTIVE:dev}
  </code></pre>
  
  <p>Any suggestions on how go about this?</p>