examples: add sms-watch-python

Add an example that watches for and prints all SMS messages of
all modems.

Signed-off-by: Dan Williams <dan@ioncontrol.co>

examples/modem-watcher-python/modem-watcher-python

@@ -33,7 +33,7 @@ def signal_handler(loop):
 def main():
     """Main routine."""
     # Create modem watcher
-    ModemWatcher.ModemWatcher()
+    ModemWatcher.ModemWatcher(None)
 
     # Main loop
     main_loop = GLib.MainLoop()