patch 8.1.0444: unnecessary check for NULL pointer

Problem:    Unnecessary check for NULL pointer.
Solution:   Remove check and call vim_free() directly.

src/version.c

@@ -792,6 +792,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    444,
 /**/
     443,
 /**/