patch 8.0.1481: clearing a pointer takes two lines

Problem:    Clearing a pointer takes two lines.
Solution:   Add vim_clear() to free and clear the pointer.

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1481,
 /**/
     1480,
 /**/