Build fails for Android apps if JAVA_HOME does not point to correct location

Trying Qt Creator for Android with a fresh user, I get a default JAVA_HOME that points to a JRE. The JRE does not have javac, only the run-time, so it cannot be used for building.

I tried setting the correct path in the Qt Creator settings, but this does not seem to have any effect.

I had to go into compile output to see the output from ant to find out what was wrong, and then quit Creator, set JAVA_HOME to the correct thing and then restart it.

I think we need both a better error message (that would probably be for 2.8 since it requires translations) and we need the settings to override the JAVA_HOME variable..