Firewall feature matching on gre-key

The promote gre-key statement is supported to configure gre-key as one of the matches in a filter. When promote gre-key is configured and gre-key is used in any of the terms in a filter, the entire filter is compiled in a way that optimizes its performance for gre-key matching. The promote gre-key configuration statement is configured at the [edit firewall family family-name filter filter-name] hierarchy level.