BUG/MINOR: vars: do not talk about global section in CLI errors for set-var

When attempting to set a variable does not start with the "proc" scope on
the CLI, we used to emit "only proc is permitted in the global section"
which obviously is a leftover from the initial code.

This may be backported to 2.4.

(cherry picked from commit c767eebf1f2130447cef3269f4a46ed164410a75)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/vars.c b/src/vars.c
index 304945f..9be146e 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -983,7 +983,7 @@
 		goto fail;
 
 	if (rule.arg.vars.scope != SCOPE_PROC) {
-		memprintf(&err, "'%s %s': cannot set variable '%s', only scope 'proc' is permitted in the global section.", args[0], args[1], args[2]);
+		memprintf(&err, "'%s %s': cannot set variable '%s', only scope 'proc' is permitted here.", args[0], args[1], args[2]);
 		goto fail;
 	}