patch 8.1.1950: using NULL pointer after an out-of-memory

Problem:    Using NULL pointer after an out-of-memory.
Solution:   Check for NULL pointer. (Dominique Pelle, closes #4881)
diff --git a/src/version.c b/src/version.c
index c406005..156f075 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1950,
+/**/
     1949,
 /**/
     1948,