Merge remote-tracking branch 'bonzini/migration-writev' into staging

# By Paolo Bonzini
# Via Paolo Bonzini
* bonzini/migration-writev:
  qemu-file: do not use stdio for qemu_fdopen
  iov: handle partial writes from sendmsg and recvmsg
  iov: reorganize iov_send_recv, part 3
  iov: reorganize iov_send_recv, part 2
  iov: reorganize iov_send_recv, part 1
  qemu-file: drop socket_put_buffer

Message-id: 1366192012-14872-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>