cm: Remove ahbottomnavigation library

We aren't currently using this. The only reason why this was
being synced, was because it's a dependency of the rebased
Gallery app.

Since the Gallery rebase is currently stalled, remove the library
for now.

This essentially reverts commit 58a76138.

Change-Id: I029979484ec3c695aebbe90eb2a32fc23aaa24f1