git-gc --auto: move threshold check to need_to_gc() function.

That is where we decide if we are going to run gc
automatically.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-gc.c

@@ -80,6 +80,13 @@ static int need_to_gc(void)
 	int num_loose = 0;
 	int needed = 0;
 
+	/*
+	 * Setting gc.auto to 0 or negative can disable the
+	 * automatic gc
+	 */
+	if (gc_auto_threshold <= 0)
+		return 0;
+
 	if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 		warning("insanely long object directory %.*s", 50, objdir);
 		return 0;
@@ -129,8 +136,6 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 			continue;
 		}
 		if (!strcmp(arg, "--auto")) {
-			if (gc_auto_threshold <= 0)
-				return 0;
 			auto_gc = 1;
 			continue;
 		}