implement getRepoSizes

At this point the RepoSize database is getting populated, and it
all seems to be working correctly. Incremental updates still need to be
done to make it performant.

Limit.hs

@@ -598,12 +598,10 @@ limitFullyBalanced mu getgroupmap groupname = Right $ MatchFiles
 		let groupmembers = fromMaybe S.empty $
 			M.lookup g (uuidsByGroup gm)
 		maxsizes <- getMaxSizes
-		-- XXX do not calc this every time!
-		(sizemap, sha) <- calcBranchRepoSizes
-		sizemap' <- journalledRepoSizes sizemap sha
+		sizemap <- getRepoSizes
 		let keysize = fromMaybe 0 (fromKey keySize key)
 		currentlocs <- S.fromList <$> loggedLocations key
-		let hasspace u = case (M.lookup u maxsizes, M.lookup u sizemap') of
+		let hasspace u = case (M.lookup u maxsizes, M.lookup u sizemap) of
 			(Just (MaxSize maxsize), Just (RepoSize reposize)) ->
 				if u `S.member` currentlocs
 					then reposize <= maxsize