[KARAF-2500] Karaf should monitor the lock file existence

git-svn-id: https://svn.apache.org/repos/asf/karaf/branches/karaf-2.x@1529091 13f79535-47bb-0310-9956-ffa450edef68
[KARAF-2499] Karaf should exit if the data directory is deleted

git-svn-id: https://svn.apache.org/repos/asf/karaf/branches/karaf-2.x@1529092 13f79535-47bb-0310-9956-ffa450edef68