http: create function end_url_with_slash

The logic to append a slash to the url if necessary in quote_ref_url
(added in 113106e0 "http.c: use strbuf API in quote_ref_url") has been
moved to a new function, end_url_with_slash.

The method takes a strbuf, the URL, and the path to be appended to the
URL. It first adds the URL to the strbuf. It then appends a slash
if the URL does not end with a slash.

The check on ref in quote_ref_url for a slash at the beginning has been
removed as a result of using end_url_with_slash. This check is not
needed, because slashes will be quoted anyway.
Signed-off-by: NTay Ray Chuan <rctay89@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

http.c

@@ -620,6 +620,7 @@ void finish_all_active_slots(void)
 		}
 }
 
+/* Helpers for modifying and creating URLs */
 static inline int needs_quote(int ch)
 {
 	if (((ch >= 'A') && (ch <= 'Z'))
@@ -640,15 +641,20 @@ static inline int hex(int v)
 		return 'A' + v - 10;
 }
 
+static void end_url_with_slash(struct strbuf *buf, const char *url)
+{
+	strbuf_addstr(buf, url);
+	if (buf->len && buf->buf[buf->len - 1] != '/')
+		strbuf_addstr(buf, "/");
+}
+
 static char *quote_ref_url(const char *base, const char *ref)
 {
 	struct strbuf buf = STRBUF_INIT;
 	const char *cp;
 	int ch;
 
-	strbuf_addstr(&buf, base);
-	if (buf.len && buf.buf[buf.len - 1] != '/' && *ref != '/')
-		strbuf_addstr(&buf, "/");
+	end_url_with_slash(&buf, base);
 
 	for (cp = ref; (ch = *cp) != 0; cp++)
 		if (needs_quote(ch))