ocfs2: Fix bogus error message from ocfs2_global_read_info

'status' variable in ocfs2_global_read_info() is always != 0 when leaving the
function because it happens to contain number of read bytes. Thus we always log
error message although everything is OK. Since all error cases properly call
mlog_errno() before jumping to out_err, there's no reason to call mlog_errno()
on exit at all. This is a fallout of c1e8d35e

 (conversion of mlog_exit()
calls).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Joel Becker <jlbec@evilplan.org>