consistently don't show sizes of empty repositories

This used to be the case, and when matching options are used, that code
path still omits them, so also omit them in the getRepoSize code path.

Command/Info.hs

@@ -654,7 +654,7 @@ cachedAllRepoData = do
  	usereposizes s = do
 		sizemap <- lift $ getRepoSizes True
 		deadset <- lift $ S.fromList <$> trustGet DeadTrusted
-		let sizemap' = M.withoutKeys sizemap deadset
+		let sizemap' = M.filter (> 0) $ M.withoutKeys sizemap deadset
 		lift $ unlessM (null <$> getUnmergedRefs)
 			warnunmerged
 		return $ s