CP-4318: Handle v6d not running when creating software_version

Signed-off-by: John Else <john.else@citrix.com>
CP-4318: Fall back to free edition if v6d is not running at startup

Signed-off-by: John Else <john.else@citrix.com>
CP-4319: Detect socket count in v6client.ml

Sending the socket count in the params list to V6client.apply_edition is
a bad idea, since this function also sends the current
Host.license_params, which may also contain the socket count, to v6d.

Instead, we update the license_params map with the socket count before
sending it to v6d.

This also means that the correct socket count is sent to v6d at xapi
startup.

Signed-off-by: John Else <john.else@citrix.com>