patch 8.1.1015: quickfix buffer shows up in list, can't get buffer number

Problem:    Quickfix buffer shows up in list, can't get buffer number.
Solution:   Make the quickfix buffer unlisted when the quickfix window is
            closed.  get the quickfix buffer number with getqflist().
            (Yegappan Lakshmanan, closes #4113)

src/version.c

@@ -779,6 +779,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1015,
 /**/
     1014,
 /**/