Want to keep this commit separate so that we can easily remove
when we no longer want to support both prefixes.
- If this server receives a "$GR." message, it takes the subject
and tries to process this locally. If there is no cluster race
reply may be received ok (like before).
- If this server sends a routed reply, it detects if sending to
an older server (then uses $GR.) or not (then uses $GNR)
- Gateway INFO has a new field that indicates if the server is
using the new prefix.
Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
8a8695d07c