inet: Restore SO_REUSEADDR in case of rollback

tcp_repair_off implicitly modifies SO_REUSEADDR option
inside the kernel (thanks avagin@ for pointing this
feature out) thus if we are to rollback and restore
the former settings of socket -- don't forget to
repair this particular one.

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