LU-5706 tests: Ensure preconditions in conf-sanity/57

LU-5706 tests: Ensure preconditions in conf-sanity/57

The modules need to be loaded to read any data, but the system does
not need to be mounted.  Loading modules prevents any skipped tests
causing this one to fail.

Test-Parameters: mdsfilesystemtype=zfs mdtfilesystemtype=zfs ostfilesystemtype=zfs testlist=conf-sanity envdefinitions="CONF_SANITY_EXCEPT=56"
Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Change-Id: Idf7003067c6ea9f33203f219f5b370008a43fafd
Reviewed-on: http://review.whamcloud.com/12236
Tested-by: Jenkins
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>