Fix r14202 (!!): this validates the protocol against the regex for the second time...

Fix r14202 (!!): this validates the protocol against the regex for the second time (preg_split has already made sure it matches wfUrlProtocols() so no need), and uses strpos() to validate against a regex (that's just wrong). I'm removing it not because it's useless but because it breaks for URL protocols that don't contain a ':' ('//' in my case) for no reason at all. Found out about this when writing parser tests for it (will commit these in a minute), so yay tests!