change Remote.repo to Remote.getRepo

This is groundwork for letting a repo be instantiated the first time
it's actually used, instead of at startup.

The only behavior change is that some old special cases for xmpp remotes
were removed. Where before git-annex silently did nothing with those
no-longer supported remotes, it may now fail in some way.

The additional IO action should have no performance impact as long as
it's simply return.

This commit was sponsored by Boyd Stephen Smith Jr. on Patreon

Assistant/TransferSlots.hs

@@ -106,13 +106,13 @@ runTransferThread' program batchmaker d run = go
  - already have been updated to include the transfer. -}
 genTransfer :: Transfer -> TransferInfo -> TransferGenerator
 genTransfer t info = case transferRemote info of
-	Just remote 
-		| Git.repoIsLocalUnknown (Remote.repo remote) -> do
-			-- optimisation for removable drives not plugged in
+	Just remote -> ifM (unpluggedremovabledrive remote)
+		( do
+			-- optimisation, since the transfer would fail
 			liftAnnex $ recordFailedTransfer t info
 			void $ removeTransfer t
 			return Nothing
-		| otherwise -> ifM (liftAnnex $ shouldTransfer t info)
+		, ifM (liftAnnex $ shouldTransfer t info)
 			( do
 				debug [ "Transferring:" , describeTransfer t info ]
 				notifyTransfer
@@ -124,11 +124,15 @@ genTransfer t info = case transferRemote info of
 				finishedTransfer t (Just info)
 				return Nothing
 			)
+		)
 	_ -> return Nothing
   where
 	direction = transferDirection t
 	isdownload = direction == Download
 
+	unpluggedremovabledrive remote = Git.repoIsLocalUnknown
+		<$> liftAnnex (Remote.getRepo remote)
+
 	{- Alerts are only shown for successful transfers.
 	 - Transfers can temporarily fail for many reasons,
 	 - so there's no point in bothering the user about