restore: disable repair mode in post_open()

A disabling repair mode drops SO_REUSEADDR.

We can set SO_REUSEADDR after disabling repair mode, but
a small race window exists in this case.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>