Add test to verify DHCP port IP address modification

When the IP address from a subnet DHCP port is changed, the route to the
metadata provisioned for that port should be modified accordingly
In case this route is not correctly updated, the server will not be
able to obtain metadata information - hence, it will not get the
ssh authorized keys

This new test only applies to OVN

Related-Bug: #1942794

Change-Id: I76e75db469e2518ed90561430aa9c8c68846dae5
1 file changed