builtin/clone: move around setup_reference()

In a subsequent commit, `setup_reference()` will start to call
`copy_alternates()`. Prepare for this by moving the function further
down so that we can avoid adding a declaration.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/clone.c

@@ -179,16 +179,6 @@ static int add_one_reference(struct string_list_item *item, void *cb_data)
 	return 0;
 }
 
-static void setup_reference(void)
-{
-	int required = 1;
-	for_each_string_list(&option_required_reference,
-			     add_one_reference, &required);
-	required = 0;
-	for_each_string_list(&option_optional_reference,
-			     add_one_reference, &required);
-}
-
 static void copy_alternates(struct strbuf *src, const char *src_repo)
 {
 	/*
@@ -228,6 +218,16 @@ static void copy_alternates(struct strbuf *src, const char *src_repo)
 	fclose(in);
 }
 
+static void setup_reference(void)
+{
+	int required = 1;
+	for_each_string_list(&option_required_reference,
+			     add_one_reference, &required);
+	required = 0;
+	for_each_string_list(&option_optional_reference,
+			     add_one_reference, &required);
+}
+
 static void mkdir_if_missing(const char *pathname, mode_t mode)
 {
 	struct stat st;