qemu-ga: Document intentional fall through in channel_event_cb() For clarity, and to hush up Coverity. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>