generator/android: write explicit LOCAL_MODULE_FILENAME for executables.
generator/android: write explicit LOCAL_MODULE_FILENAME for executables.

Without this, executables beginning with 'lib' will have the 'lib' prefix
unexpectedly stripped.

mumble-voip/libmumble-gyp,mumble-voip/libmumble-gyp,mumble-voip/libmumble-gyp,mumble-voip/libmumble-gyp