TIF: fix callback cleanup logic in removeSessionStateLocked().

Adding DeathRecipient to callback instance is enough. removeSessionStateLocked()
can be called in normal session release case, and the current logic will remove
valid callback instances.
Also, ConcurrentModificationException in abortPendingCreateSessionRequestsLocked()
is fixed.

Bug: 17212681
Change-Id: I42cacfa33086bf9182b061553ff52c0e25d94d9b