patch 7.4.1647

Problem:    Using freed memory after setqflist() and ":caddbuffer".  (Dominique)
Solution:   Set qf_ptr when adding the first item to the quickfix list.

src/version.c

@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1647,
 /**/
     1646,
 /**/