LU-3803 test: refine sanity test_161c

LU-3803 test: refine sanity test_161c

The test 161c is assume the $tdir will be in MDT0, but
actually $tdir(161d) left by 161a and 161b will be on
MDT1, which will make 161 fails, so delete $tdir before
testing 161c.

Add interop test condition.

Add more console output infomation.

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Change-Id: Id40c63c3c81d32565e393850c4448c30e0d2e693
Reviewed-on: http://review.whamcloud.com/7439
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>