revwalk: style change

Change the condition for returning 0 more in line with that we write
elsewhere in the library.

src/revwalk.c

@@ -489,9 +489,7 @@ static int everybody_uninteresting(git_commit_list *orig)
 	while (list) {
 		git_commit_list_node *commit = list->item;
 		list = list->next;
-		if (commit->uninteresting)
-			continue;
-
+		if (!commit->uninteresting)
 			return 0;
 	}