LU-9741 test: Correct check of stripe count for directories

LU-9741 test: Correct check of stripe count for directories

With the progressive file layout feature, the 'lfs getstripe -d'
output will report stripe count for each component. Since
sanity test 27w checks that there is only one "stripe_count"
line in the 'lfs getstripe -d' output, this needs to be changed
to check that there is at least one "stripe_count" reported.

Test-Parameters: trivial
Signed-off-by: James Nunez <james.a.nunez@intel.com>
Change-Id: I51f141b2542e65d1bc296cb2cb14c12f22afdcec
Reviewed-on: https://review.whamcloud.com/27980
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Saurabh Tandan <saurabh.tandan@intel.com>
Reviewed-by: Wei Liu <wei3.liu@intel.com>