strip HTTP auth credentials from base when printing

fix for https://github.com/williamh/pybugz/issues/76

instead of:
* Info: Using [novell] (https://user:pass@apibugzilla.novell.com/xmlrpc.cgi)

print:
* Info: Using [novell] (https://apibugzilla.novell.com/xmlrpc.cgi)