Fix fixed_ips tests to skip if ip not found

Current fixed ips tests fetch the ip from server['addresses']
and call API with that ip. but it does not check if there is no
ip. That can occur when no addresses information in 'addresses'
field.

Let's skip those test if no ip is found on server side.

Change-Id: Ide965998b2d49886823e62643057c05698613169
2 files changed