Use explicit script path in test_maxctrl

The path to the script is now explicitly defined. This makes the call
unambiguous as the home directory depends on the current user.

maxscale-system-test/test_maxctrl.cpp

@@ -27,7 +27,8 @@ int main(int argc, char *argv[])
 
     test.tprintf("Starting test");
     test.verbose = true;
-    int rv = test.ssh_maxscale(true, "export maxscale2_API=%s:8989; ./test_maxctrl.sh", test.galera->IP[3]);
+    int rv = test.ssh_maxscale(true, "export maxscale_access_homedir=%s; export maxscale2_API=%s:8989; ./test_maxctrl.sh",
+                               test.maxscale_access_homedir, test.galera->IP[3]);
     test.verbose = false;
 
     test.tprintf("Removing NPM");

maxscale-system-test/test_maxctrl.sh

@@ -20,7 +20,7 @@ fi
 cd MaxScale/maxctrl
 
 # Create the scripts that start and stop MaxScale
-~/maxctrl_scripts.sh
+$maxscale_access_homedir/maxctrl_scripts.sh
 chmod +x *.sh
 
 npm i