tools: ratbagctl: shout the usage if the parsing is incomplete

Too easy to trigger ("ratbagctl.devel profile" is just enough), so we
probably better have a proper usage call here.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>

tools/ratbagctl.devel.in

@@ -52,7 +52,13 @@ def main(argv):
         if cmd.help:
             parser.print_help()
         else:
-            cmd.func(ratbagd, cmd)
+            try:
+                f = cmd.func
+            except AttributeError:
+                parser.print_help()
+                return
+            else:
+                f(ratbagd, cmd)
     finally:
         try:
             if cmd.keepalive:

tools/ratbagctl.in

@@ -1356,7 +1356,13 @@ def main(argv):
 
     r = open_ratbagd()
     if r is not None:
-        cmd.func(r, cmd)
+        try:
+            f = cmd.func
+        except AttributeError:
+            parser.print_help()
+            return
+        else:
+            f(r, cmd)
 
 if __name__ == "__main__":
     main(sys.argv[1:])