channel-webdav: include comment about message handling
channel-webdav: include comment about message handling

Channel-webdav does not handle any other message besides
SPICE_MSG_SPICEVMC_DATA it wants to let SpiceVmcInputStream handle it
and the same to deal when sending data to the server with
SPICE_MSGC_SPICEVMC_DATA using SpiceVmcOutputStream.

The other Spice messages are dealt in its parent class channel-port
and handled in channel-webdav handling port-event signal.

This patch also renames webdav_handle_msg -> webdav_handle_data_msg
for the reason described above.

Signed-off-by: Victor Toso <39b7599ff73bbf5db531748ba5250f21fa7120ff@redhat.com>
Reviewed-by: Marc-André Lureau <a6f2b960a4aca61381fc650a67901b2ac8e83e6d@redhat.com>

fgouget/spice-gtk,fgouget/spice-gtk,fgouget/spice-gtk,flexVDI/spice-gtk,flexVDI/spice-gtk