Add proper cluster testing scripts

The scripts start MaxScale processes on two different servers. The support
framework for the tests is in place but the tests themselves still need to
be modified to allow the use of non-localhost addresses.

maxscale-system-test/testconnections.cpp

@@ -68,6 +68,25 @@ void TestConnections::multiple_maxscales(bool value)
     maxscale::multiple_maxscales = value;
 }
 
+void TestConnections::set_secondary_maxscale(const char* ip_var, const char* ip6_var)
+{
+    const char* ip = getenv(ip_var);
+    const char* ip6 = getenv(ip6_var);
+
+    if (ip || ip6)
+    {
+        TestConnections::multiple_maxscales(true);
+        if (ip)
+        {
+            setenv("maxscale2_IP", ip, 1);
+        }
+        if (ip6)
+        {
+            setenv("maxscale2_network6", ip6, 1);
+        }
+    }
+}
+
 TestConnections::TestConnections(int argc, char *argv[]):
     enable_timeouts(true),
     global_result(0),