Merge remote-tracking branch 'remotes/stefanha/tags/net-pull-request' into staging

Pull request

These two .can_receive() are now reviewed.  The net subsystem queue for 2.4 is now empty.

# gpg: Signature made Tue Jul 28 13:26:03 2015 BST using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/net-pull-request:
  xen: Drop net_rx_ok
  hw/net: handle flow control in mcf_fec driver receiver

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>