tty: Fix compilation warrning

 | tty.c: In function ‘tty_restore_ctl_terminal’:
 | include/criu-log.h:42:16: error: ‘index’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

Same time assign CONSOLE_INDEX for debug info.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>