LU-3812 tests: check Lustre version in sanity-scrub test 10b

LU-3812 tests: check Lustre version in sanity-scrub test 10b

This patch adds Lustre version check codes into sanity-scrub
test 10b to make the test work with servers which have the
following patch:

Lustre-commit: f5491211ed7251a45e4e6916539cd2a2ab5e6038
Lustre-change: http://review.whamcloud.com/6343

Test-Parameters: envdefinitions=SLOW=yes,ENABLE_QUOTA=yes \
clientdistro=el6 serverdistro=el6 clientarch=x86_64 \
serverarch=x86_64 serverjob=lustre-master serverbuildno=1666 \
testlist=sanity-scrub

Signed-off-by: Jian Yu <jian.yu@intel.com>
Change-Id: I66646a27fc30399fcb718a961362800988d7175e
Reviewed-on: http://review.whamcloud.com/7529
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Wei Liu <wei3.liu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>