patch 8.0.0980: Coverity warning for failing to open /dev/null

Problem:    Coverity warning for failing to open /dev/null.
Solution:   When /dev/null can't be opened exit the child.
diff --git a/src/version.c b/src/version.c
index 5d97014..c8ae297 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    980,
+/**/
     979,
 /**/
     978,