LU-614 test: speed up needlessly long tests

LU-614 test: speed up needlessly long tests

Some tests are running needlessly long compared to the value that
they provide, and can be made much faster without any loss in value.

conf-sanity test_53a: run llverdev in partial mode always
conf-sanity test_53b: run llverfs in partial mode always
sanity test_220: use unlinkmany instead of "rm -rf", but could likely
                 be sped up dramatically via CFS_FAIL_LOC() on OST

Change-Id: Ifbe66bffc051b6163e41a9bffb1d6b1ab6304e94
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/1266
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>