fix PUT to http proxied special remote

It was hanging because it never sent FAILURE in the INVALID case.
And putoffset always triggers the INVALID case.

Annex/Proxy.hs

@@ -175,7 +175,7 @@ proxySpecialRemote protoversion r ihdl ohdl owaitv endv = go
 							Just (VALIDITY Valid) ->
 								store
 							Just (VALIDITY Invalid) ->
-								return ()
+								liftIO $ sendmessage FAILURE
 							_ -> giveup "protocol error"
 						else store
 				_ -> giveup "protocol error"

doc/todo/git-annex_proxies.mdwn

@@ -28,11 +28,8 @@ Planned schedule of work:
 
 ## work notes
 
-* test http server proxying with special remotes
-
-  git-annex get --from origin-d works
-  git-annex drop --from origin-d works
-  git-annex copy --to origin-d HANGS
+* shut down of a connection to a http proxied special remote may not work
+  properly
 
 * Make http server support clusters.