LU-1648 llog: prevent journal to restart for llog cancel

LU-1648 llog: prevent journal to restart for llog cancel

Journal credit for llog cancel should include the blocks for
deleting the inode. Otherwise the journal handle may need to
be restarted during the transaction for more credit. Then it
may be blocked with holding llog_handle::lgh_lock, which may
cause deadlock with other llog operations those have started
journal handle but waiting for the llog_handle::lgh_lock.

port of master patch 8d334f67052ccf77713c780a8040593728977599

Signed-off-by: Fan Yong <yong.fan@whamcloud.com>
Signed-off-by: Liu Ying <emoly.liu@intel.com>
Change-Id: I4013eb764485c282ed2443d02556c3377e16c936
Reviewed-on: http://review.whamcloud.com/4743
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Niu Yawei <niu@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>