fix GIT_SSH_COMMAND -n parameter

It was being passed to sh, not to the command, oops. Noticed because it
broke the test suite on OSX, where sh -n silently does nothing. Would
also break on Linux when eg posh was being used as the shell; bash
ignores the -n.

This commit was supported by the NSF-funded DataLad project.

Git/Ssh.hs

@@ -34,7 +34,10 @@ type SshCommand = String
 -- | Checks for GIT_SSH and GIT_SSH_COMMAND and if set, returns
 -- a command and parameters to run to ssh.
 gitSsh :: SshHost -> Maybe SshPort -> SshCommand -> IO (Maybe (FilePath, [CommandParam]))
-gitSsh host mp cmd = do
+gitSsh host mp cmd = gitSsh' host mp cmd []
+
+gitSsh' :: SshHost -> Maybe SshPort -> SshCommand -> [CommandParam] -> IO (Maybe (FilePath, [CommandParam]))
+gitSsh' host mp cmd extrasshparams = do
 	gsc <- getEnv gitSshCommandEnv
 	case gsc of
 		Just c
@@ -42,24 +45,27 @@ gitSsh host mp cmd = do
 			-- when it contains spaces; otherwise it's
 			-- treated the same as GIT_SSH
 			| any isSpace c -> ret "sh"
-				[ [ Param "-c"
-				  , Param (shellcmd c gitps)
-				  ]
+				[ Param "-c"
+				, Param (shellcmd c sshps)
 				]
-			| otherwise -> ret c [gitps]
+			| otherwise -> ret c sshps
 		Nothing -> do
 			gs <- getEnv gitSshEnv
 			case gs of
-				Just c -> ret c [gitps]
+				Just c -> ret c sshps
 				Nothing -> return Nothing
  where
-	ret c ll = return $ Just (c, concat ll)
+	ret c l = return $ Just (c, l)
 
-	-- git passes exactly these parameters to the command
+	-- Git passes exactly these parameters to the ssh command.
 	gitps = map Param $ case mp of
 		Nothing -> [host, cmd]
 		Just p -> [host, "-p", show p, cmd]
 
+	-- Passing any extra parameters to the ssh command may
+	-- break some commands.
+	sshps = extrasshparams ++ gitps
+
 	-- The shell command to run with sh -c is constructed
 	-- this way, rather than using "$@" because there could be some
 	-- unwanted parameters passed to the command, and this way they