Bumping AOSP Contacts version to 1.4.15 am: d2ac793647 am: 149a9d7853
am: 6e430c2b10

* commit '6e430c2b104a700af51de2ec017ef4c2f3995dba':

Change-Id: I5cb4cf4e437d9aec17b6eaa8809c3c2f48141bf4