ext4: lost brelse in ext4_read_inode()

One of error path in ext4_read_inode() leaks bh since brelse is forgoten.

Signed-off-by: Kirill Korotaev <dev@openvz.org>
Acked-by: Vasily Averin <vvs@sw.ru>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>