patch 7.4.871

Problem:    Vim leaks memory, when 'wildignore' filters out all matches.
Solution:   Free the files array when it becomes empty.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    871,
 /**/
     870,
 /**/