headers_lib: rename Android.bp

Renaming Android.bp to Androidbp is done to avoid compilation
failure reported for SA* targets.

Ignore tracking of Android.bp link file.

Change-Id: Ie36f8bf5e0ac011e5f82e4cbd3c2cc7d6bf14070
Signed-off-by: Prateek Sood <prsood@codeaurora.org>