e2fsck: free bh when descriptor block checksum fails

e2fsck: free bh when descriptor block checksum fails

Free the buffer head if the journal descriptor block fails checksum
verification.  This has been patched before (see "e2fsck: free bh on
csum verify error in do_one_pass") but apparently the patch was never
committed to jbd2 in the kernel, so when we resync'd the recovery code
with 3.16, the bug came back.  Sigh.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>