Append port to trusted domain in case it's not 80 or 443

See https://github.com/owncloud/core/pull/10584#issuecomment-54677059 for reference.

@ronnicek Can you please test this change? Thanks.

\cc @MTRichards FYI. 
How is changing return to exit related to "Append port to trusted domain in case it's not 80 or 443"?