Move a couple of commmon bits of code out to utils.go

utils.go

@@ -97,3 +97,22 @@ func (lop ListOfPeers) Swap(i, j int) {
 func (lop ListOfPeers) Less(i, j int) bool {
 	return lop[i].Name < lop[i].Name
 }
+
+func StripPortFromAddr(address string) string {
+	// If we've been given a port number, take it off
+	if addrHost, _, err := net.SplitHostPort(address); err == nil {
+		return addrHost
+	}
+	return address
+}
+
+// given an address like '1.2.3.4:567', return the address if it has a port,
+// otherwise return the address with weave's standard port number
+func NormalisePeerAddr(peerAddr string) string {
+	_, _, err := net.SplitHostPort(peerAddr)
+	if err == nil {
+		return peerAddr
+	} else {
+		return fmt.Sprintf("%s:%d", peerAddr, Port)
+	}
+}