Build host:port with net.JoinHostPort in HAProxy tests
Build host:port with net.JoinHostPort in HAProxy tests

This test is failing on e2e-metal-ipi-ovn-ipv6, because it uses
fmt.Sprintf to construct the host:port section of a URL.

sallyom/origin,bparees/origin,mfojtik/origin,gabemontero/origin,jsafrane/origin,akram/origin,soltysh/origin,bparees/origin,mfojtik/origin,mahak/origin,deads2k/origin,akram/origin,mahak/origin,openshift/origin,soltysh/origin,jsafrane/origin,gabemontero/origin,deads2k/origin,deads2k/origin,hroyrh/origin,bparees/origin,csrwng/origin,gabemontero/origin,akram/origin,mfojtik/origin,jsafrane/origin,sallyom/origin,csrwng/origin,mahak/origin,csrwng/origin,soltysh/origin,hroyrh/origin,openshift/origin,openshift/origin,hroyrh/origin,sallyom/origin