virNetClientStreamQueuePacket: Set st->incomingEOF on the end of stream

virNetClientStreamQueuePacket: Set st->incomingEOF on the end of stream

While reworking client side of streams, I had to postpone payload
decoding so that stream holes and stream data can be
distinguished in virNetClientStreamRecvPacket. That's merely what
18944b7aea46d does. However, I accidentally removed one important
bit: when server sends us an empty STREAM packet (with no
payload) - meaning end of stream - st->incomingEOF flag needs to
be set. It used to be before I touched the code. After I removed
it, virNetClientStreamRecvPacket will try to fetch more data from
the stream, but it will never come.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>