sim_vehicle.py: roughly fix auto-sysid functionality

Tools/autotest/sim_vehicle.py

@@ -769,7 +769,7 @@ def start_vehicle(binary, opts, stuff, spawns=None):
                 print("The parameter file (%s) does not exist" % (x,))
                 sys.exit(1)
         path = ",".join(paths)
-        if cmd_opts.count > 1:
+        if cmd_opts.count > 1 or opts.auto_sysid:
             # we are in a subdirectory when using -n
             path = os.path.join("..", path)
         progress("Using defaults from (%s)" % (path,))