clean up url removal presence update

* rmurl: Fix a case where removing the last url left git-annex thinking
  content was still present in the web special remote.
* SETURLPRESENT, SETURIPRESENT, SETURLMISSING, and SETURIMISSING
  used to update the presence information of the external special remote
  that called them; this was not documented behavior and is no longer done.

Done by making setUrlPresent and setUrlMissing only update presence info
for the web, and only when the url is a web url. See the comment for
reasoning about why that's the right thing to do.

In AddUrl, had to make it update location tracking, to handle the
non-web-url case.

This commit was sponsored by Ewen McNeill on Patreon.

Assistant/Upgrade.hs

@@ -83,7 +83,7 @@ startDistributionDownload d = go =<< liftIO . newVersionLocation d =<< liftIO ol
   where
 	go Nothing = debug ["Skipping redundant upgrade"]
 	go (Just dest) = do
-		liftAnnex $ setUrlPresent webUUID k u
+		liftAnnex $ setUrlPresent k u
 		hook <- asIO1 $ distributionDownloadComplete d dest cleanup
 		modifyDaemonStatus_ $ \s -> s
 			{ transferHook = M.insert k hook (transferHook s) }
@@ -100,7 +100,7 @@ startDistributionDownload d = go =<< liftIO . newVersionLocation d =<< liftIO ol
 		}
 	cleanup = liftAnnex $ do
 		lockContentForRemoval k removeAnnex
-		setUrlMissing webUUID k u
+		setUrlMissing k u
 		logStatus k InfoMissing
 
 {- Called once the download is done.