TrebuchetQuickstepGo: Select proper launcher manifest

TrebuchetQuickstepGo launcher manifest is go/AndroidManifest-launcher.xml
and since LauncherGoResLib is its dependency, selecting a different
launcher manifest (quickstep/AndroidManifest-launcher.xml) would result
in two main launcher activities defined in the final application manifest.
That causes obvious issues during first boot because Android would think
that there are two launchers.

Change-Id: Ib575af8373999eabf101801639de041c84a0e91d