bluetooth: Show a refresh icon on the select devices screen

The refresh menu is hidden behind an overflow which is
pointless. This patch shows the refresh icon if there is
enough room.

Change-Id: I35f19c42054b05388f7b8fcb82e0f3bd60e2d618
TrustedCredentials: Don't crash when the activity is paused

If you press Settings -> Security -> Trusted Credentials, then press
 back before the loading finishes, the loader async task will still
try to dereference the activity which will cause an NPE.

This patch fixes that by getting and holding a reference to the
context in the beggining and bailing early if it is null.

Change-Id: Ie03734d5f184821df5d8729fc4a16eb51cdeebf5
Merge "bluetooth: Show a refresh icon on the select devices screen" into lp5.0
Merge "TrustedCredentials: Don't crash when the activity is paused" into lp5.0