QPID-5671: [linearstore] Add ability to use disk partitions and select per-queue EFPs. Modified previous code and added new code to allow a seamless updrade of the modified EFP and journal directory structure from the old to the new. The "efp" directory is removed from the directory tree containing the EFPs in a partition and all directories are moved up a level. The journal files are replaced with symlinks as they are used and replaced into the EFP.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1637985 13f79535-47bb-0310-9956-ffa450edef68