http.c: free preq when aborting

Free preq in new_http_pack_request when aborting. preq was allocated
before jumping to the 'abort' label so this is safe.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http.c

@@ -1059,6 +1059,7 @@ struct http_pack_request *new_http_pack_request(
 
 abort:
 	free(filename);
+	free(preq);
 	return NULL;
 }