Introduces an API for encoding the header field for outgoing messages
allowing some duplicated code to be eliminated
* qemud/dispatch.c, qemud/dispatch.h: add remoteEncodeClientMessageHeader
for encoding message header. Update remoteDispatchClientRequest to
use this method.
* qemud/remote.c: Update remoteDispatchDomainEventSend to use the
generic remoteEncodeClientMessageHeader() for encoding event
message hedaders. Push some logic from remoteRelayDomainEvent
down into remoteDispatchDomainEventSend.
Separate the decoding of incoming request header out from the
dispatch code. This will allow later code to making dispatcher
routing decisions based on the header field data.
* qemud/dispatch.c, qemud/dispatch.h: Add remoteDecodeClientMessageHeader
API for decoding the header of a client message. Update the
remoteDispatchClientRequest method to assume a pre-decoded
header.
* qemud/qemud.h: Include a 'remote_message_header' field in
'struct qemud_client_message' for pre-decoded header data
* qemud/qemud.c: Decode the incoming client message header before
invoking remoteDispatchClientRequest
