fs/samba: fix noceph mount point

We need to clean this dir up at the end of the test or else teuthology
will be unhappy with the dirty testdir.  Use the localdir which does this
properly.

Signed-off-by: Sage Weil <sage@inktank.com>
fs/samba: disable smbtorture lock test

Until we fix #5025.

Signed-off-by: Sage Weil <sage@inktank.com>