Added annex.gnupg-decrypt-options and remote.<name>.annex-gnupg-decrypt-options, which are passed to gpg when it's decrypting data.

The naming is unofrtunately not consistent, but the gnupg-options
were only used for encrypting, and it's too late to change that.

It would be nice to have a third setting that is always passed to gnupg,
but ~/.gnupg/options can be used to specify such global options when really
needed.

Remote/Helper/Special.hs

@@ -178,7 +178,8 @@ specialRemote' cfg c preparestorer prepareretriever prepareremover preparecheckp
 		}
 	cip = cipherKey c
 	isencrypted = isJust (extractCipher c)
-	gpgopts = getGpgEncParams encr
+	gpgencopts = getGpgEncParams encr
+	gpgdecopts = getGpgDecParams encr
 
 	safely a = catchNonAsync a (\e -> warning (show e) >> return False)
 
@@ -200,7 +201,7 @@ specialRemote' cfg c preparestorer prepareretriever prepareremover preparecheckp
 	storechunk (Just (cipher, enck)) storer k content p = do
 		cmd <- gpgCmd <$> Annex.getGitConfig
 		withBytes content $ \b ->
-			encrypt cmd gpgopts cipher (feedBytes b) $
+			encrypt cmd gpgencopts cipher (feedBytes b) $
 				readBytes $ \encb ->
 					storer (enck k) (ByteContent encb) p
 
@@ -210,7 +211,7 @@ specialRemote' cfg c preparestorer prepareretriever prepareremover preparecheckp
 	  where
 		go (Just retriever) = displayprogress p k $ \p' ->
 			retrieveChunks retriever (uuid baser) chunkconfig
-				enck k dest p' (sink dest enc)
+				enck k dest p' (sink dest enc gpgdecopts)
 		go Nothing = return False
 		enck = maybe id snd enc
 
@@ -245,23 +246,24 @@ specialRemote' cfg c preparestorer prepareretriever prepareremover preparecheckp
 sink
 	:: FilePath
 	-> Maybe (Cipher, EncKey)
+	-> [CommandParam]
 	-> Maybe Handle
 	-> Maybe MeterUpdate
 	-> ContentSource
 	-> Annex Bool
-sink dest enc mh mp content = do
+sink dest enc gpgdecopts mh mp content = do
 	case (enc, mh, content) of
 		(Nothing, Nothing, FileContent f)
 			| f == dest -> noop
 			| otherwise -> liftIO $ moveFile f dest
 		(Just (cipher, _), _, ByteContent b) -> do
 			cmd <- gpgCmd <$> Annex.getGitConfig
-			decrypt cmd cipher (feedBytes b) $
+			decrypt cmd gpgdecopts cipher (feedBytes b) $
 				readBytes write
 		(Just (cipher, _), _, FileContent f) -> do
 			cmd <- gpgCmd <$> Annex.getGitConfig
 			withBytes content $ \b ->
-				decrypt cmd cipher (feedBytes b) $
+				decrypt cmd gpgdecopts cipher (feedBytes b) $
 					readBytes write
 			liftIO $ nukeFile f
 		(Nothing, _, FileContent f) -> do