http-push: prevent format overflow warning with gcc >= 9

In function 'finish_request',
    inlined from 'process_response' at http-push.c:248:2:
http-push.c:587:4: warning: '%s' directive argument is null [-Wformat-overflow=]
  587 |    fprintf(stderr, "Unable to get pack file %s\n%s",
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  588 |     request->url, curl_errorstr);
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

request->url is needed for the error message if there was a failure
during fetch but was being cleared unnecessarily earlier.

note that the leak is prevented by calling release_request unconditionally
at the end.

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Suggested-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/http-push.c b/http-push.c
index b22c7ca..f56cd91 100644
--- a/http-push.c
+++ b/http-push.c
@@ -525,8 +525,8 @@
 	if (request->headers != NULL)
 		curl_slist_free_all(request->headers);
 
-	/* URL is reused for MOVE after PUT */
-	if (request->state != RUN_PUT) {
+	/* URL is reused for MOVE after PUT and used during FETCH */
+	if (request->state != RUN_PUT && request->state != RUN_FETCH_PACKED) {
 		FREE_AND_NULL(request->url);
 	}