partially complete gcrypt remote (local send done; rest not)

This is a git-remote-gcrypt encrypted special remote. Only sending files
in to the remote works, and only for local repositories.

Most of the work so far has involved making initremote work. A particular
problem is that remote setup in this case needs to generate its own uuid,
derivied from the gcrypt-id. That required some larger changes in the code
to support.

For ssh remotes, this will probably just reuse Remote.Rsync's code, so
should be easy enough. And for downloading from a web remote, I will need
to factor out the part of Remote.Git that does that.

One particular thing that will need work is supporting hot-swapping a local
gcrypt remote. I think it needs to store the gcrypt-id in the git config of the
local remote, so that it can check it every time, and compare with the
cached annex-uuid for the remote. If there is a mismatch, it can change
both the cached annex-uuid and the gcrypt-id. That should work, and I laid
some groundwork for it by already reading the remote's config when it's
local. (Also needed for other reasons.)

This commit was sponsored by Daniel Callahan.

Assistant/MakeRemote.hs

@@ -68,8 +68,8 @@ makeRsyncRemote name location = makeRemote name location $ const $ void $
 	go =<< Command.InitRemote.findExisting name
   where
   	go Nothing = setupSpecialRemote name Rsync.remote config
-		=<< Command.InitRemote.generateNew name
-	go (Just v) = setupSpecialRemote name Rsync.remote config v
+		(Nothing, Command.InitRemote.newConfig name)
+	go (Just (u, c)) = setupSpecialRemote name Rsync.remote config (Just u, c)
 	config = M.fromList
 		[ ("encryption", "shared")
 		, ("rsyncurl", location)
@@ -89,7 +89,7 @@ initSpecialRemote name remotetype config = go 0
 		r <- Command.InitRemote.findExisting fullname
 		case r of
 			Nothing -> setupSpecialRemote fullname remotetype config
-				=<< Command.InitRemote.generateNew fullname
+				(Nothing, Command.InitRemote.newConfig fullname)
 			Just _ -> go (n + 1)
 
 {- Enables an existing special remote. -}
@@ -98,15 +98,15 @@ enableSpecialRemote name remotetype config = do
 	r <- Command.InitRemote.findExisting name
 	case r of
 		Nothing -> error $ "Cannot find a special remote named " ++ name
-		Just v -> setupSpecialRemote name remotetype config v
+		Just (u, c) -> setupSpecialRemote name remotetype config (Just u, c)
 
-setupSpecialRemote :: RemoteName -> RemoteType -> R.RemoteConfig -> (UUID, R.RemoteConfig) -> Annex RemoteName
-setupSpecialRemote name remotetype config (u, c) = do
+setupSpecialRemote :: RemoteName -> RemoteType -> R.RemoteConfig -> (Maybe UUID, R.RemoteConfig) -> Annex RemoteName
+setupSpecialRemote name remotetype config (mu, c) = do
 	{- Currently, only 'weak' ciphers can be generated from the
 	 - assistant, because otherwise GnuPG may block once the entropy
 	 - pool is drained, and as of now there's no way to tell the user
 	 - to perform IO actions to refill the pool. -}
-	c' <- R.setup remotetype u $
+	(c', u) <- R.setup remotetype mu $
 		M.insert "highRandomQuality" "false" $ M.union config c
 	describeUUID u name
 	configSet u c'