FELIX-4312 - avoid pointless service interruptions:

- when the configuration of the HTTP Jetty service isn't changed,
  do not restart the server;
- avoid visibility of partial configurations during an update of the
  configuration.



git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1540691 13f79535-47bb-0310-9956-ffa450edef68