Stop testing after the first IPv6 relay server

mist/mist.cpp

@@ -1490,12 +1490,11 @@ int main(int argc, char* argv[])
                         return 0;
                     }
                 }
-                else {
-                    // Tested against a working server and it failed
+
+                // Tested against a IPv6 working server
                 break;
             }
         }
-        }
 
         freeaddrinfo(result);