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

# gpg: Signature made Wed May 27 11:02:55 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:
  net/net: Record usage status of mac address
  tap: Improve -netdev/netdev_add/-net/... tap error reporting
  tap: Finish conversion of tap_open() to Error
  tap-solaris: Convert tap_open() to Error
  tap-bsd: Convert tap_open() to Error
  tap-linux: Convert tap_open() to Error
  tap: Permit incremental conversion of tap_open() to Error
  tap: Convert launch_script() to Error
  tap: Convert net_init_tap_one() to Error
  tap: Convert tap_set_sndbuf() to Error
  tap: Improve -netdev/netdev_add/-net/... bridge error reporting
  tap: net_tap_fd_init() can't fail, drop dead error handling
  net/dump: Improve -net/host_net_add dump error reporting
  net: Improve -net nic error reporting
  net: Permit incremental conversion of init functions to Error
  net: Improve error message for -net hubport a bit
  net: Change help text to list -netdev instead of -net by default

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