clean_service_url should remove `&' if there're other params in query.
clean_service_url should remove `&' if there're other params in query.

Signed-off-by: Matt Zukowski <1fa2ef4755a9226cb9a0a4840bd89b158ac71391@zukowski.ca>
infoman/rubycas-server,chowells79/rubycas-server,DiegoSalazar/ROR-RubyCAS-Server,intinno/ruby-cas-server,geo767/rubycas-server,rubycas/rubycas-server,chowells79/rubycas-server,geo767/rubycas-server,rubycas/rubycas-server,Windermere/rubycas-server,acsellers/cas,infoman/rubycas-server,intinno/ruby-cas-server,Windermere/rubycas-server,adamdruppe/rubycas-server,DiegoSalazar/ROR-RubyCAS-Server,identification-io/rubycas-server,chowells79/rubycas-server,acsellers/cas,jay3126/ruby_cas_server,geo767/rubycas-server,Windermere/rubycas-server,identification-io/rubycas-server,infoman/rubycas-server,rubycas/rubycas-server,identification-io/rubycas-server,adamdruppe/rubycas-server,jay3126/ruby_cas_server,adamdruppe/rubycas-server