[HttpFoundation] fix checkip6

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

I have this error ContextErrorException: Warning: inet_pton(): Unrecognized address X.X.X.X:X
in IpUtils.php line 110

X.X.X.X:X is detected as a ipv6 because HTTP_X_FORWARDED_FOR have a port.