Remove needless locking of mRulesLock that caused deadlocks.

The locks were added in c006f1 when underlying functions weren't performing
locking.  In d2a45875 the underlying functions were changed to perform locking
but the higher level locking wasn't removed.  The higher level locking can
now cause deadlocks with the new NetworkAgentInfo locking.  This change
removes the needless higher level locking.  Now all mRulesLock locking
only guards simple accesses to the appropriate two data strucures so there is
no chance of a deadlock.  I verified that all accesses to the appropriate
two data structures are guarded by mRulesLock locking.

bug:17569997
Change-Id: Id9f4e3d19d6895876925ae32f12460db30359368