[STORE] Add dedicated method to write temporary files

Recovery writes temporary files which might not end up in the
right distributor directories today. This commit adds a dedicated
API that allows specifying the target file name in order to create the
tempoary file in the correct directory.
can we add a one lliner java doc explaining why this is needed (rather then pass through the the primary lock factory)? it's non-trivial to figure it is done to track the location of the lock file, if it's using files..