ocfs2: delete unnecessary checks before brelse()

brelse() tests whether its argument is NULL and then returns immediately.
Thus the tests around the shown calls are not needed.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/55cde320-394b-f985-56ce-1a2abea782aa@web.de
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>