patch 8.2.4754: using cached values after unsetting some environment variables

Problem:    Still using cached values after unsetting some known environment
            variables.
Solution:   Take care of the side effects. (closes #10194)
diff --git a/src/version.c b/src/version.c
index 97683b4..e833b78 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4754,
+/**/
     4753,
 /**/
     4752,