- parse_index -> parse_pty_index since it's PTY specific
 - pty_is_master -> tty_is_master because it will test
   not only PTY peers but other types as well
 - pty_is_hung -> tty_is_hung for same reason
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>