rsync shellescape disable option

Rsync special remotes can be configured with shellescape=no to avoid shell
quoting that is normally done when using rsync over ssh. This is known to
be needed for certian rsync hosting providers (specificially
hidrive.strato.com) that use rsync over ssh but do not pass it through the
shell.

Remote/Rsync.hs

@@ -22,9 +22,10 @@ import Utility.RsyncFile
 
 type RsyncUrl = String
 
-data RsyncOpts = RsyncOpts {
-	rsyncUrl :: RsyncUrl,
-	rsyncOptions :: [CommandParam]
+data RsyncOpts = RsyncOpts
+	{ rsyncUrl :: RsyncUrl
+	, rsyncOptions :: [CommandParam]
+	, rsyncShellEscape :: Bool
 }
 
 remote :: RemoteType
@@ -37,7 +38,7 @@ remote = RemoteType {
 
 gen :: Git.Repo -> UUID -> Maybe RemoteConfig -> Annex Remote
 gen r u c = do
-	o <- genRsyncOpts r
+	o <- genRsyncOpts r c
 	cst <- remoteCost r expensiveRemoteCost
 	return $ encryptableRemote c
 		(storeEncrypted o)
@@ -58,11 +59,13 @@ gen r u c = do
 			remotetype = remote
 		}
 
-genRsyncOpts :: Git.Repo -> Annex RsyncOpts
-genRsyncOpts r = do
+genRsyncOpts :: Git.Repo -> Maybe RemoteConfig -> Annex RsyncOpts
+genRsyncOpts r c = do
 	url <- getRemoteConfig r "rsyncurl" (error "missing rsyncurl")
-	opts <- getRemoteConfig r "rsync-options" ""
-	return $ RsyncOpts url $ map Param $ filter safe $ words opts
+	opts <- map Param . filter safe . words
+		<$> getRemoteConfig r "rsync-options" ""
+	let escape = maybe True (\m -> M.lookup "shellescape" m /= Just "no") c
+	return $ RsyncOpts url opts escape
 	where
 		safe o
 			-- Don't allow user to pass --delete to rsync;
@@ -86,7 +89,7 @@ rsyncSetup u c = do
 
 rsyncEscape :: RsyncOpts -> String -> String
 rsyncEscape o s
-	| rsyncUrlIsShell (rsyncUrl o) = shellEscape s
+	| rsyncShellEscape o && rsyncUrlIsShell (rsyncUrl o) = shellEscape s
 	| otherwise = s
 
 rsyncUrls :: RsyncOpts -> Key -> [String]