Catch PermissionDenied exception on security_group_update so that we can return proper error when sg rule quota is exceeded.

Change-Id: I1ebfe45a50521653ec92f115e12b692cc554dec4
Closes-Bug: 1365463
Merge "Catch PermissionDenied exception on security_group_update so that we can return proper error when sg rule quota is exceeded." into R1.10