FELIX-3946 Prevent NPE in BundlesServlet.bundleDetails

* BundleInfoProvider: Clarify webConsoleRoot may be null
* BundlesServlet: Guard pluginRoot against null (only get substring if not null)
* BundlesServlet: Fix rendition of "nfo" structure generated based
  on BundleInforProvider data
* ServicesUsedInfoProvider: Generate BundleInfo of type VALUE if
  webConsoleRoot is null

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1452202 13f79535-47bb-0310-9956-ffa450edef68