btrfs/315: update filter to match mount cmd

Mount error info changed since util-linux v2.40
(91ea38e libmount: report failed syscall name).
So update _filter_mount_error() to match it.

Signed-off-by: An Long <lan@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>
1 file changed