auxiliary/scanner/http/soap_xml cleanup

During lunch I was poking at a device I have at home that has a SOAP interface.  It is very flaky and soap_xml wasn't being particularly nice about it.

This:

* Corrects Ruby style (most) everywhere
* Uses Rex's sleep, converts to milliseconds -- seconds are too granular
* Moves begin/rescue inside nested verb+noun loop
* Prints errors even if not in verbose mode
* Corrects URI construction when PATH ends with /