Use a safe list traversal while checking for duplicate vars in pbx_builtin_setvar_helper.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@243486 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/pbx.c

@@ -5937,14 +5937,15 @@ void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const
 			nametail++;
 	}
 
-	AST_LIST_TRAVERSE (headp, newvariable, entries) {
+	AST_LIST_TRAVERSE_SAFE_BEGIN(headp, newvariable, entries) {
 		if (strcasecmp(ast_var_name(newvariable), nametail) == 0) {
 			/* there is already such a variable, delete it */
-			AST_LIST_REMOVE(headp, newvariable, entries);
+			AST_LIST_REMOVE_CURRENT(headp, entries);
 			ast_var_delete(newvariable);
 			break;
 		}
 	}
+	AST_LIST_TRAVERSE_SAFE_END;
 
 	if (value) {
 		if ((option_verbose > 1) && (headp == &globals))