LU-5424 tests: Disable sanity-sec test 4

With patch from LU-4367 the somewhat incorrect assumption
of the test about availability of dentry is broken and
the test always fails.
Disable the test for now until it's fixed one way or another.

Change-Id: I0759f4ab7022bc072bb2480eaba0b19ff0f5101d
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Reviewed-on: http://review.whamcloud.com/11631
Tested-by: Jenkins