store: introduce a main_file_path method for revlog This help code that need to point revlog to an index file. This is put to use in the upgrade code.

upgrade: actually use StoreEntry API to create revlog Lets make use of the semanctic of the object we are passed.

upgrade: use StoreEntry object in upgrade We will make more use of the API in the next changeset, but just moving to use entry is a significant change for the engine codebase.

upgrade: drop a quick fix that is not longer necessary We won't issue bad revlog from topfile anymore.

store: use StoreEntry API instead of parsing filename in largefile This is more explicit and more robust.

store: use StoreEntry API instead of parsing filename when listing manifestlog This is more explicit and more robust.

store: use StoreEntry API instead of parsing filename when fixing issue6528 This is more explicit and more robust. We also introduce a small output change as it make things simpler and this is a affecting a debug-command.

store: use StoreEntry API instead of parsing filename in remotefilelog This is more explicit and more robust.

store: use StoreEntry API instead of parsing filename in narrow This is more explicit and more robust.

store: add a `target_id` attribute on RevlogStoreEntry This hold the "target" (file, directory, etc) of a revlog. Having this available will help a lot of code to avoid direct file path access.