MRP-1800 mgc: fix lost wakeup and new test

fix lost wakeup to reenqueue configs after fail.
and introduce a new test for MRP-1800

Signed-off-by: Alexey Lyashkov <alexey_lyashkov@xyratex.com>
Change-Id: I1aa292c29f1e063ed88b401c01931eab553a95f8
Reviewed-on: http://es-gerrit.xyus.xyratex.com:8080/1915
Tested-by: Jenkins
Tested-by: Elena Gryaznova <elena_gryaznova@xyratex.com>
Reviewed-by: Andriy Skulysh <andriy_skulysh@xyratex.com>
Reviewed-by: Rahul Deshmukh <rahul_deshmukh@xyratex.com>
Reviewed-by: Vitaly Fertman <vitaly_fertman@xyratex.com>
MRP-1800 mgc: fix race with start mgc vs reenqueue lock

fix race between release fs reference while update llog in
background. fix ability to store an updated config after initial
fail.

Signed-off-by: Alexey Lyashkov <alexey_lyashkov@xyratex.com>
Change-Id: Ic62e04f093e6aecb681bc95dd2c29496e9965419
Reviewed-on: http://es-gerrit.xyus.xyratex.com:8080/1990
Tested-by: Jenkins
Tested-by: Elena Gryaznova <elena_gryaznova@xyratex.com>
Reviewed-by: Rahul Deshmukh <rahul_deshmukh@xyratex.com>
Reviewed-by: Andriy Skulysh <andriy_skulysh@xyratex.com>
Reviewed-by: Vitaly Fertman <vitaly_fertman@xyratex.com>