LU-5905 tests: add version check codes to conf-sanity test 56

LU-5905 tests: add version check codes to conf-sanity test 56

This patch adds Lustre version check codes into conf-sanity test
56 to make the test interoperate with servers that do not have
the following changes:

Lustre-commit: 3dc232918c7c9b95398ac6a0dc4c2130adc2851d
Lustre-change: http://review.whamcloud.com/12145
or
Lustre-commit: e6745116cc372647f785c4063389734620c92e91
Lustre-change: http://review.whamcloud.com/12319

Test-Parameters: alwaysuploadlogs envdefinitions=ONLY=56 \
ossjob=lustre-b2_4 mdsjob=lustre-b2_4 ossbuildno=73 mdsbuildno=73 \
testlist=conf-sanity

Signed-off-by: Jian Yu <jian.yu@intel.com>
Change-Id: I903d9d5779cedd5b73a903b3b0d46c102ab038fd
Reviewed-on: http://review.whamcloud.com/13046
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Li Wei <wei.g.li@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>