better directory handling

Rename Locations functions for better consitency, and make their values
more consistent too.

Used </> rather than manually building paths. There are still more places
that manually do so, but are tricky, due to the behavior of </> when
the second FilePath is absolute. So I only changed places where
it obviously was relative.

Backend/File.hs

@@ -77,7 +77,7 @@ copyKeyFile key file = do
 		-- before going on to the next remote.)
 		probablyPresent r =
 			if not $ Git.repoIsUrl r
-				then liftIO $ doesFileExist $ annexLocation r key
+				then liftIO $ doesFileExist $ gitAnnexLocation r key
 				else return True
 		docopy r continue = do
 			showNote $ "copying from " ++ Git.repoDescribe r ++ "..."

Backend/SHA1.hs

@@ -48,7 +48,7 @@ keyValue file = do
 checkKeySHA1 :: Key -> Annex Bool
 checkKeySHA1 key = do
 	g <- Annex.gitRepo
-	let file = annexLocation g key
+	let file = gitAnnexLocation g key
 	present <- liftIO $ doesFileExist file
 	if not present
 		then return True

Backend/WORM.hs

@@ -57,7 +57,7 @@ keySize key = read $ section !! 1
 checkKeySize :: Key -> Annex Bool
 checkKeySize key = do
 	g <- Annex.gitRepo
-	let file = annexLocation g key
+	let file = gitAnnexLocation g key
 	present <- liftIO $ doesFileExist file
 	if not present
 		then return True