android: fix the building rules for Android 5.0

android: fix the building rules for Android 5.0

Android 5.0 allows modules to generate source into $OUT/gen, which will
then be copied into $OUT/obj and $OUT/obj_$(TARGET_2ND_ARCH) as necessary.
Modules will need to change calls to local-intermediates-dir into
local-generated-sources-dir.

The patch changes local-intermediates-dir into local-generated-sources-dir.
If the Android version is less than 5.0, fallback to local-intermediates-dir.

The patch also fixes the 64-bit building issue of Android 5.0.

v2 [Emil Velikov]
 - Keep the LOCAL_UNSTRIPPED_PATH variable.

Signed-off-by: Chih-Wei Huang <cwhuang@linux.org.tw>