prevent failure for meta: reset_connection

now plugins that don't explicitly support it give a warning.

lib/ansible/plugins/connection/__init__.py

@@ -278,3 +278,6 @@ class ConnectionBase(with_metaclass(ABCMeta, object)):
         f = self._play_context.connection_lockfd
         fcntl.lockf(f, fcntl.LOCK_UN)
         display.vvvv('CONNECTION: pid %d released lock on %d' % (os.getpid(), f), host=self._play_context.remote_addr)
+
+    def reset(self):
+        display.warning("Reset is not implemented for this connection")