patch 8.1.0543: Coverity warns for leaking memory and using wrong struct

Problem:    Coverity warns for leaking memory and using wrong struct.
Solution:   Free pointer when allocation fails. Change "boff" to "loff".
            (closes #3634)
diff --git a/src/version.c b/src/version.c
index 82b8abe..2d7f2e6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -793,6 +793,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    543,
+/**/
     542,
 /**/
     541,