ocfs2: adjust code style for o2net_handler_tree_lookup()

Code in o2net_handler_tree_lookup() may be corrupted by mistake.  So
adjust it to promote readability.
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>