patch 9.0.0997: Coverity warns for dead code

Problem:    Coverity warns for dead code.
Solution:   Don't use ASCII_ISUPPER() for a negative value.

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    997,
 /**/
     996,
 /**/