LU-2177 ldlm: flock completion fixes.

LU-2177 ldlm: flock completion fixes.

move checks for FAILED, DESTROYED flags under ldlm spinlock,
destroy flock atomically with the check it is not destroyed yet.

do not put the granted flock into the resource if this is
UNLOCK, TEST, or DEADLOCK'ed flock.

a set of flock tests which races reply completion for
new flock request/test flock/unlock with namespace cleanup
on eviction.

Signed-off-by: Vitaly Fertman <vitaly_fertman@xyratex.com>
Change-Id: I97fa040a26eda6c6728929d10b29c2316db663e3
Reviewed-by: Alexey Lyashkov <alexey_lyashkov@xyratex.com>
Reviewed-by: Andriy Skulysh <andriy_skulysh@xyratex.com>
Tested-by: Alexander Lezhoev <alexander_lezhoev@xyratex.com>
Reviewed-by: Vitaly Fertman <vitaly_fertman@xyratex.com>
Xyratex-bug-id: MRP-1588
Reviewed-on: http://review.whamcloud.com/10005
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>