SEC-1619: Added check in GAE sample for change of Google user while still logged into the app.

Also updated GAE version and build script. Uploading to GAE now works when run from the gradle build file using the command 'gradle gaeDeploy'.

buildSrc/src/main/groovy/gae/GaePlugin.groovy

@@ -20,7 +20,7 @@ class GaePlugin implements Plugin<Project> {
         project.gaeDeploy.dependsOn project.war
 
         project.war.doLast {
-          ant.unzip(src: project.war.archivePath, dest: explodedWar)
+            ant.unzip(src: project.war.archivePath, dest: explodedWar)
         }
     }
 }