ocfs2: fix error handling when creating debugfs root in ocfs2_init()

Error handling if creation of root of debugfs in ocfs2_init() fails is
broken.  Although error code is set we fail to exit ocfs2_init() with
error and thus initialization ends with success.  Later when mounting a
filesystem, ocfs2 debugfs entries end up being created in the root of
debugfs filesystem which is confusing.

Fix the error handling to bail out.

Coverity id: 1227009.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-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>