UBIFS: simplify returns

Directly return recover_head() and ubifs_leb_unmap()
instead of storing value in err and testing it.

Change-Id: I2e169473a437b0919acb25ffebbd685a846ea9c1
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Git-commit: 8a87dc55f75f19ffdbb52066afea1b633577c79f
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>