convert WebDAV to new special remote interface, adding new-style chunking support

Reusing http connection when operating on chunks is not done yet,
I had to submit some patches to DAV to support that. However, this is no
slower than old-style chunking was.

Note that it's a fileRetriever and a fileStorer, despite DAV using
bytestrings that would allow streaming. As a result, upload/download of
encrypted files is made a bit more expensive, since it spools them to temp
files. This was needed to get the progress meters to work.

There are probably ways to avoid that.. But it turns out that the current
DAV interface buffers the whole file content in memory, and I have
sent in a patch to DAV to improve its interfaces. Using the new interfaces,
it's certainly going to need to be a fileStorer, in order to read the file
size from the file (getting the size of a bytestring would destroy
laziness). It should be possible to use the new interface to make it be a
byteRetriever, so I'll change that when I get to it.

This commit was sponsored by Andreas Olsson.

Remote/Helper/Encryptable.hs

@@ -14,9 +14,7 @@ import Types.Remote
 import Crypto
 import Types.Crypto
 import qualified Annex
-import Config.Cost
 import Utility.Base64
-import Utility.Metered
 
 {- Encryption setup for a remote. The user must specify whether to use
  - an encryption key, or not encrypt. An encrypted cipher is created, or is
@@ -70,42 +68,6 @@ encryptionSetup c = maybe genCipher updateCipher $ extractCipher c
                 -- remotes (while being backward-compatible).
 		[ "keyid", "keyid+", "keyid-", "highRandomQuality" ]
 
-{- Modifies a Remote to support encryption. -}
--- TODO: deprecated
-encryptableRemote
-	:: RemoteConfig
-	-> ((Cipher, Key) -> Key -> MeterUpdate -> Annex Bool)
-	-> ((Cipher, Key) -> Key -> FilePath -> MeterUpdate -> Annex Bool)
-	-> Remote
-	-> Remote
-encryptableRemote c storeKeyEncrypted retrieveKeyFileEncrypted r = r
-	{ storeKey = \k f p -> cip k >>= maybe
-		(storeKey r k f p)
-		(\v -> storeKeyEncrypted v k p)
-	, retrieveKeyFile = \k f d p -> cip k >>= maybe
-		(retrieveKeyFile r k f d p)
-		(\v -> retrieveKeyFileEncrypted v k d p)
-	, retrieveKeyFileCheap = \k d -> cip k >>= maybe
-		(retrieveKeyFileCheap r k d)
-		(\_ -> return False)
-	, removeKey = \k -> cip k >>= maybe
-		(removeKey r k)
-		(\(_, enckey) -> removeKey r enckey)
-	, checkPresent = \k -> cip k >>= maybe
-		(checkPresent r k)
-		(\(_, enckey) -> checkPresent r enckey)
-	, cost = maybe
-		(cost r)
-		(const $ cost r + encryptedRemoteCostAdj)
-		(extractCipher c)
-	}
-  where
-	cip k = do
-		v <- cipherKey c
-		return $ case v of
-			Nothing -> Nothing
-			Just (cipher, enck) -> Just (cipher, enck k)
-
 {- Gets encryption Cipher. The decrypted Ciphers are cached in the Annex
  - state. -}
 remoteCipher :: RemoteConfig -> Annex (Maybe Cipher)