Handling non-obvious relative URLs

When importing WSDL from WebService published as a Proxy on WSO2 ESB,
the relative WSDL imports are translated in particular way, for example:

    schemaLocation="VRMValuationService?xsd=http://test.valesb.etgws.co.uk/v1.0.0.11/VRMValuationService.svc?xsd=xsd1"/>

this *is* relative URL, but simple `location.indexOf( "://" ) == -1` is
not enough to detect it. So I've used quite simple RegExp.