title: unable to deploy after upgrading to 1.7.4
body: <p>I upgraded today to GAE 1.7.4 and on trying to deploy I see following error:</p>
  
  <pre><code>Preparing to deploy:
      Created staging directory at: 'C:\Users\VSKUMA~1.ST-\AppData\Local\Temp\appcfg4811921061542689032.tmp'
      Scanning for jsp files.
      Compiling jsp files.
  java.lang.RuntimeException: Cannot get the System Java Compiler. Please use a JDK, not a JRE.
  </code></pre>
  
  <p>I already have JDK pointing in the build path and this all was working fine till GAE 1.7.3 </p>
  
  <p>I cannot uninstall the existing GREs for some reasons. </p>