The server that solicits a LeafNode connection does not send an
INFO, so the accepting side had no way to know if the remote
supports headers or not. The solicit side will now send the headers
support capability in the CONNECT protocol so that the receiving
side can mark the inbound connection with headers support based
on that and its own support for headers.
Resolves#1781
Signed-off-by: Ivan Kozlovic <ivan@synadia.com>