common/filter: filter out extra mount error output

common/filter: filter out extra mount error output

The lastest mount command (from util-linux) merged below commit:
  79534c0d7e0f ("mount: add hint about dmesg(8) to error messages")
which brought in a new error output when mount fails, no matter
ro/rw/busy mount fails.

That cause some cases (e.g. xfs/005) fail as:
  mount: Structure needs cleaning
         dmesg(1) may have more information after failed mount system call

More failed cases like generic/050, ext4/002, xfs/154, xfs/158 etc.
Especially xfs/154 and xfs/158, need to change their _filter_scratch
to _filter_error_mount.

Signed-off-by: Zorro Lang <zlang@kernel.org>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>