MRP-1266 ldlm_flock_deadlock() ASSERTION( req != lock ) failed

Abort processing of flock blockers list
on reaching disconnected export

Change-Id: Ifbe546486d9c3aad870c4a5cc300bfc586f14609
Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com>
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/621
Tested-by: Jenkins
Reviewed-by: Alexander Boyko <Alexander_Boyko@xyratex.com>
Reviewed-by: Alexey Lyashkov <Alexey_Lyashkov@xyratex.com>
Tested-by: Elena Gryaznova <Elena_Gryaznova@xyratex.com>
Reviewed-by: Denis Kondratenko <Denis_Kondratenko@xyratex.com>