xfstests: stop special casing nfs and udf

For historical reasons beyond my knowledge xfstests tries to abuse the
scratch device as test device for nfs and udf.  Because not all test
have inherited the right usage of the _setup_testdir and _cleanup_testdir
helpers this leads to lots of unessecary test failures.

Remove the special casing, which gets nfs down to a minimal number of
failures.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Sugned-off-by: Dave Chinner <david@fromorbit.com>

tests/udf/098

@@ -81,8 +81,6 @@ _supported_os IRIX
 _require_scratch
 _require_attrs
 
-_setup_testdir
-
 cd $SCRATCH_MNT
 
 echo "create file foo"

tests/udf/102

@@ -36,7 +36,6 @@ _cleanup()
 {
     rm -f $tmp.*
     cd /
-    _cleanup_testdir
 }
 # get standard environment, filters and checks
 . ./common/rc