reset our buffer each iteration when doing variable substitution

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@327512 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/pbx.c

@@ -3620,6 +3620,9 @@ void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, str
 	ast_str_reset(*buf);
 	whereweare = tmp = templ;
 	while (!ast_strlen_zero(whereweare)) {
+		/* reset our buffer */
+		ast_str_reset(substr3);
+
 		/* Assume we're copying the whole remaining string */
 		pos = strlen(whereweare);
 		nextvar = NULL;