Now we can use the --inherit-fd option to mark external terminals on dump
and to tell which file desdriptors should be used to restore these terminals.

Here is an example how it works:
$ setsid sleep 1000

$ ipython
In [1]: import os
In [2]: st = os.stat("/proc/self/fd/0")
In [3]: print "tty[%x:%x]" % (st.st_rdev, st.st_dev)
tty:[8800:d]

$ps -C sleep
  PID TTY          TIME CMD
 4109 ?        00:00:00 sleep

$ ./criu dump --external 'tty[8800:d]' -D imgs -v4 -t 4109
$ ./criu restore --inherit-fd 'fd[1]:tty[8800:d]' -D imgs -v4

v2: add missed break
    remove @non_file from tty_driver
Signed-off-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>