patch 8.1.2147: crash when allocating memory fails

Problem:    Crash when allocating memory fails. (Zu-Ming Jiang)
Solution:   Check that 'spellcapcheck' is not NULL. (closes #5048)
diff --git a/src/version.c b/src/version.c
index a6a9439..3dc64cc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2147,
+/**/
     2146,
 /**/
     2145,