FELIX-4484 only mark DPs as stale after successful uninstall:

- if an uninstall fails, we should be able to call uninstallForced to
  retry it. When the DP is already marked as stale, this wouldn't work.



git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1587490 13f79535-47bb-0310-9956-ffa450edef68