CompileJava does not delete generated sources

[oehme]

This line should also look at the generated sources dir. This was already fixed for incremental builds, but wasn't done for full builds.

[oehme]

@eriwen Though this is not a 4.7 regression, it is an unfortunate oversight in our annotation processing story. I have fixed this for incremental compiles in 4.7, but missed the fact that we weren't doing it right for full compiles either. I'm tempted to do a 4.7 RC2 for this. What do you think?