Fixed create_port with fixed_ips for public network

Fixed create_port with fixed_ips for public network

RM9593
Minor style note: It might be easier to read a for..else construct for L433-L439. 
```
for ip_address in ip_addresses:
    _try_reallocate_ip_address(ip_address)
else: 
    _try_reallocate_ip_address()
```