Control identity plugin reauthentication

Identity plugins will by default re-authenticate themselves if they are
about to expire. This is generally correct however there are times where
this re-authentication doesn't make sense and we should be able to
prevent it.

Closes-Bug: #1352051
Change-Id: I66b50b1e650501e7f076139895473e8d1791ce27
Merge "Control identity plugin reauthentication"