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.

Command/AddUrl.hs

@@ -233,7 +233,8 @@ addUrlChecked o url file u checkexistssize key =
 			(exists, samesize, url') <- checkexistssize key
 			if exists && (samesize || relaxedOption (downloadOptions o))
 				then do
-					setUrlPresent u key url'
+					setUrlPresent key url'
+					logChange key u InfoPresent
 					next $ return True
 				else do
 					warning $ "while adding a new url to an already annexed file, " ++ if exists
@@ -397,7 +398,8 @@ addWorkTree u url file key mtmp = case mtmp of
   where
 	go = do
 		maybeShowJSON $ JSONChunk [("key", key2file key)]
-		setUrlPresent u key url
+		setUrlPresent key url
+		logChange key u InfoPresent
 		ifM (addAnnexedFile file key mtmp)
 			( do
 				when (isJust mtmp) $

Command/Migrate.hs

@@ -17,7 +17,6 @@ import qualified Command.Fsck
 import qualified Annex
 import Logs.MetaData
 import Logs.Web
-import qualified Remote
 
 cmd :: Command
 cmd = notDirect $ withGlobalOptions [annexedMatchingOptions] $
@@ -78,9 +77,8 @@ perform file oldkey oldbackend newbackend = go =<< genkey (fastMigrate oldbacken
 			-- If the old key had some associated urls, record them for
 			-- the new key as well.
 			urls <- getUrls oldkey
-			forM_ urls $ \url -> do
-				r <- Remote.claimingUrl url
-				setUrlPresent (Remote.uuid r) newkey url
+			forM_ urls $ \url ->
+				setUrlPresent newkey url
 			next $ Command.ReKey.cleanup file oldkey newkey
 		, error "failed"
 		)

Command/RegisterUrl.hs

@@ -69,5 +69,5 @@ perform key url = do
 perform' :: Key -> URLString -> Annex Bool
 perform' key url = do
 	r <- Remote.claimingUrl url
-	setUrlPresent (Remote.uuid r) key (setDownloader' url r)
+	setUrlPresent key (setDownloader' url r)
 	return True

Command/RmUrl.hs

@@ -49,5 +49,5 @@ start (file, url) = flip whenAnnexed file $ \_ key -> do
 cleanup :: String -> Key -> CommandCleanup
 cleanup url key = do
 	r <- Remote.claimingUrl url
-	setUrlMissing (Remote.uuid r) key (setDownloader' url r)
+	setUrlMissing key (setDownloader' url r)
 	return True