MXS-2243 System tests brings VMs by themselves (#193)

maxscale-system-test changed in order to control test environment by itself.
Every test checks which machines are running, compare with list of needed machines
and start new VMs is they are missing in the running machines list.
Tests are executiong MDBCI commands, MDBCI executable should be in the PATH

maxscale-system-test/lots_of_rows.cpp

@@ -31,7 +31,7 @@ int main(int argc, char* argv[])
 
     Test->tprintf("done, syncing slaves");
     Test->stop_timeout();
-    Test->repl->sync_slaves();
+    Test->galera->sync_slaves();
     Test->tprintf("Trying SELECT");
     Test->set_timeout(60);
     Test->try_query(Test->maxscales->conn_rwsplit[0], (char*) "SELECT * FROM t1");