FS-Cache: Add transition to handle invalidate immediately after lookup 
FS-Cache: Add transition to handle invalidate immediately after lookup 

Add a missing transition to the FS-Cache object state machine to handle an
invalidation event occuring between the back end completing the object lookup
by calling fscache_obtained_object() (which moves to state OBJECT_AVAILABLE)
and the backend returning to fscache_lookup_object() and thence to
fscache_object_state_machine() which then does a goto lookup_transit to handle
the transition - but lookup_transit doesn't handle EV_INVALIDATE.

Without this, the following BUG can be logged:

	FS-Cache: Unsupported event 2 [5/f7] in state OBJECT_AVAILABLE
	------------[ cut here ]------------
	kernel BUG at fs/fscache/object.c:357!

Where event 2 is EV_INVALIDATE.

Signed-off-by: David Howells <ebac1d06c1688626821bb0e574a037a7a5354e49@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas