Fix log update-status error

This patch adds a dummy update_status function so that the update-status
hook 'has' a function to run and thus silence the log error.

Change-Id: I6a73943af9609810f1e40789c8d351278843dece
Closes-bug: #1837639

hooks/cinder_hooks.py

@@ -262,6 +262,12 @@ def post_series_upgrade():
     clear_unit_upgrading()
 
 
+@hooks.hook('update-status')
+def dummy_update_status():
+    """Dummy function to silence missing hook log entry"""
+    pass
+
+
 if __name__ == '__main__':
     try:
         hooks.execute(sys.argv)