base

Fixing bugs due to the new custom accessibility action APIs.

1. AccessibiltiyAction was incorectly throwing an exception when
   a custom action was constructed.

2. AccessibilityManagerService should no longer enforce only standard
   actions as we allow custom ones too.

bug:15110963

Change-Id: Iea57e0a6449b87bd8d103c55ca255e80705f2565