LU-2181 tests: test failure on conf-sanity, subtest 23a

LU-2181 tests: test failure on conf-sanity, subtest 23a

Disable subtests that do umount with mds down in SLES11 SP2.
Problems with upstream umount command cause hangs.

Test-Parameters: fortestonly, clientdistro=sles11sp2, \
		 envdefinitions=SANITY_EXCEPT=39l

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: I3d5f0c02dcc0deef1d38e2d1a09c8ed6cf2b295f
Reviewed-on: http://review.whamcloud.com/4639
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>