LU-12706 tests: sanity-quota 4a sync timeout fix

LU-12706 tests: sanity-quota 4a sync timeout fix

Don't sync all OSTs in a system - this might take
too much time. Instead, set striping only on OST0000
and sync only MDTs and OST0000. This fix is against
the following failure:

  FAIL: Passed grace time 20, 1566910527, 1566910563

Lustre-change: https://review.whamcloud.com/55216
Lustre-commit: 9e7b239bbd26b601127073bb0c6789cb9def7073

Signed-off-by: Sergey Cheremencev <scherementsev@ddn.com>
Change-Id: I525e6c73c6d14a126a2bde7d92bc28f11f3c78c8
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/55470
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>