Add expected response checks of secgroup rules

"add security group rule" API returns additional rule in its response
body but current tests don't check the response.
This patch adds some checks of the response.
In addition, this patch removes status code checks because the codes
are already checked in client side.

Change-Id: Iab4ce492c060b8a2b79a3b3d9a6d30a359f6f312
Related-Bug: #1373832
Merge "Add expected response checks of secgroup rules"