add a whitespace in plugin's logging

Signed-off-by: allencloud <allen.sun@daocloud.io>

plugin/manager.go

@@ -252,7 +252,7 @@ func LookupWithCapability(name, capability string) (Plugin, error) {
 
 // StateChanged updates daemon inter...
 func (pm *Manager) StateChanged(id string, e libcontainerd.StateInfo) error {
-	logrus.Debugf("plugin statechanged %s %#v", id, e)
+	logrus.Debugf("plugin state changed %s %#v", id, e)
 
 	return nil
 }