Fix for few failing network rbac tests

Following network rbac api tests are failing -
    1. test_create_network_provider_physical_network
    2. test_update_network_router_external

This patch provides fix for -
    1. test_update_network_router_external

This patch removes test "test_create_network_provider_physical_network"
because it is failing.
As soon as we get a new approach for handling such "hardcoding required"
tests, a new patch can be submitted.

Partial-Bug: #1665105

Change-Id: Iff84ccfed7346fed077c449298b21cd5057f957e
2 files changed