No more dynamic upload URL, which trips up half our new users behind
reverse proxies when the camlistored process doesn't know its
forward-facing URL.
The original camlistore stat + upload protocol was influenced by App
Engine's limitations at the time, and some of our indecision about
where the Camlistore design is going. We understand the Camlistore
design now, and App Engine's former limitations are gone. Time to
clean things up.
More REST-y now too.
See http://camlistore.org/issue/123
Change-Id: I92c6552f830b925cef379c204a982a2213bf2f4b