aoeu
rewrite metadata sync

Include full and partial metadata sync, but don't worry about tags and
versions. Full and partial sync still have a bit of duplication
that could be factored out.

Save state to disk so partial syncs can know what's already been
synced.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
md full sync: skip sections that have no items (returning 404)

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
md full sync: put results in the right queue

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
md partial sync: handle 404 locking a log

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Forgot to add store.py

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
add missing module to requirements.txt

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
mdlog requests don't try to decode json response

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>