criu: Add --cpu-cap option

This option will serve to manage CPU capabilities
to be matched/ignored on restore procedure. At the
moment we introduce 'fpu','all' capability arguments.
By default 'all' is set.

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