caches.json should come from CVMFS

[djw8605]

Rather than having caches.json come from a release, it should come from somewhere on CVMFS, so we can update if a Cache is consistently down.

[djw8605]

stashcp should look several places for caches.json, including a special directory in CVMFS, and the release directory...

[matyasselmeci]

/cvmfs/stash.osgstorage.org/caches.json? If we're OK with that, it should be a one-line change.

[djw8605]

Sure. Where on the priority chain should it go?

[matyasselmeci]

I think just behind os.path.join(prefix, "etc/stashcache/caches.json") so the admin can still override it.

BTW I just noticed

StashCache/stashcp.py

Line 562 in df49515

cache_files.insert(0, resource_string(__name__, 'caches.json'))

That needs to be an append, not an insert, because we need to make the resource file the least important.

[matyasselmeci]

Never mind, I see the PR.