LU-10759 test: sanity tests need check for 2 or more OSTs

LU-10759 test: sanity tests need check for 2 or more OSTs

sanity test 27F, 311, and 314 need two or more OSTs. Add a check
on the number of OSTs in these test cases.

Test-Parameters: trivial osscount=1 ostcount=1

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Change-Id: Ie802429bfeb44ee19d8867614b420de7bceebfa2
Reviewed-on: https://review.whamcloud.com/31495
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>