LU-11678 quota: protect quota flags at OSC

LU-11678 quota: protect quota flags at OSC

There is no protection in OSC quota hash tracking the quota flags of
different qid, which could cause the previous request to modify the
quota flags which was set by the current request because the replies
could be out of order.

This patch also adds a lock to protect the operations on the quota
hash from different requests.

Test-Parameters: testlist=sanity-quota,sanity-quota,sanity-quota,sanity-quota

Change-Id: Ia6e5141265beacb9401dd533081fa0b85fd5ea6a
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/33747
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>