LU-11699 lfsck: Umount while running LFSCK

LU-11699 lfsck: Umount while running LFSCK

lod_device_free() ASSERTION( atomic_read(&lu->ld_ref) == 0)failed

Wake up master thread after releasing all refernces.

Change-Id: I2933f7c58c12f4e3cd2510b01babbf02814c8768
Cray-bug-id: LUS-6510
Signed-off-by: Andriy Skulysh <c17819@cray.com>
Reviewed-by: Alexander Boyko <c17825@cray.com>
Reviewed-by: Andrew Perepechko <c17827@cray.com>
Reviewed-on: https://review.whamcloud.com/33715
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexandr Boyko <c17825@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>