Update VIF interface to version 5

Update VIF interface to version 5

Unfortunately VIF interface version 4 suffers from a shutdown race with
the TransmitterQueuePacket method. If a call to this races with the Disable
method then a NULL callback function pointer can be invoked.
This patch fixes the race by having TransmitterQueuePacket return a status
code to indicate whether a packet has been queued (rather than invoking the
completion callback if it has not), but this necessitates a interface change
so the VIF interface version is also updated to 5 and a new PDO revision is
added.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>