Add ServerConfigPayload to InstallSnapshot message

Add ServerConfigPayload to InstallSnapshot message

When the leader installs a snapshot on a follower, it needs to include the
server config info as well. Otherwise if a server config change occurred
while a follower was down, it won't get the updated server config info
and will be out of sync with the rest of the cluster which causes other
issues.

Change-Id: Ic290ed162bf9fdf6b9fe55986ea0c9c9e83b29a9
Signed-off-by: Tom Pantelis <tpanteli@brocade.com>