patch 8.2.1899: crash in out-of-memory situation

Problem:    Crash in out-of-memory situation.
Solution:   Bail out if shell_name is NULL. (Dominique Pellé, closes #7196)
diff --git a/src/version.c b/src/version.c
index ba9c816..b4c6582 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1899,
+/**/
     1898,
 /**/
     1897,