Execute router commands with admin client (2)

The API calls that change the router external gateway info "enable_snat"
flag are, by default, allowed only for admin users. That fix is proposed
to the Neutron API definitions in [1].

This patch amends the missing bits of [2].

[1]https://review.opendev.org/c/openstack/neutron-lib/+/941631
[2]https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/941689

Related-Bug: #2098109
Change-Id: Ie496dec0e2396a232c4e4a891672e70f0d90857f
1 file changed