patch 8.1.1642: may use uninitialized variable

Problem:    May use uninitialized variable. (Patrick Palka)
Solution:   Initialize variables earlier. (closes #4623)
diff --git a/src/version.c b/src/version.c
index 663f92f..f71c75c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1642,
+/**/
     1641,
 /**/
     1640,