Deal with pkexec changing to root's home directory when running a command.

Wow, that's not documented anywhere, and seems like a major gotcha in
pkexec.

Broke enable-tor.

Command/EnableTor.hs

@@ -46,18 +46,19 @@ start os = do
 #else
 start _os = do
 #endif
-	uuid <- getUUID
-	when (uuid == NoUUID) $
-		giveup "This can only be run in a git-annex repository."
 #ifndef mingw32_HOST_OS
 	curruserid <- liftIO getEffectiveUserID
 	if curruserid == 0
-		then case readish =<< headMaybe os of
-			Nothing -> giveup "Need user-id parameter."
-			Just userid -> go uuid userid
+		then case os of
+			(uid:[]) -> go uid
+			(uid:repodir:_) -> do
+				Annex.changeDirectory repodir
+				go uid
+			_ -> giveup "Need user-id parameter."
 		else starting "enable-tor" (ActionItemOther Nothing) $ do
 			gitannex <- liftIO readProgramFile
-			let ps = [Param (cmdname cmd), Param (show curruserid)]
+			cwd <- liftIO getCurrentDirectory
+			let ps = [Param (cmdname cmd), Param (show curruserid), Param cwd]
 			sucommand <- liftIO $ mkSuCommand gitannex ps
 			maybe noop showLongNote
 				(describePasswordPrompt' sucommand)
@@ -67,14 +68,19 @@ start _os = do
 					[ "Failed to run as root:" , gitannex ] ++ toCommand ps
 				)
 #else
-	go uuid 0
+	go "0"
 #endif
   where
-	go uuid userid = do
-		(onionaddr, onionport) <- liftIO $
-			addHiddenService torAppName userid (fromUUID uuid)
-		storeP2PAddress $ TorAnnex onionaddr onionport
-		stop
+	go suserid = case readish suserid of
+		Nothing -> giveup "Unable to parse user-id parameter."
+		Just userid -> do
+			uuid <- getUUID
+			when (uuid == NoUUID) $
+				giveup "This can only be run in a git-annex repository."
+			(onionaddr, onionport) <- liftIO $
+				addHiddenService torAppName userid (fromUUID uuid)
+			storeP2PAddress $ TorAnnex onionaddr onionport
+			stop
 
 checkHiddenService :: CommandCleanup
 checkHiddenService = bracket setup cleanup go