attach: call lxc_container_new() earlier
attach: call lxc_container_new() earlier

We will reuse the newly initialized container for PR_SET_NO_NEW_PRIVS.

Signed-off-by: Christian Brauner <48455ab3070520a2d174545c7239d6d0fabd9a83@canonical.com>

aeris/lxc,aeris/lxc,thmo/lxc,ysbnim/lxc,GreatFruitOmsk/lxc,cjwatson/lxc,federicobriata/lxc,terceiro/lxc,caglar10ur/lxc,ss1h2a3tw/lxc,LynxChaus/lxc,ss1h2a3tw/lxc,ss1h2a3tw/lxc,hallyn/lxc,caglar10ur/lxc,hallyn/lxc,hallyn/lxc,cjwatson/lxc,terceiro/lxc,terceiro/lxc,hfuCN/lxc,GreatFruitOmsk/lxc,ysbnim/lxc,GreatFruitOmsk/lxc,cjwatson/lxc,federicobriata/lxc,aeris/lxc,ysbnim/lxc,thmo/lxc,LynxChaus/lxc,hfuCN/lxc,hfuCN/lxc,caglar10ur/lxc,federicobriata/lxc,LynxChaus/lxc,thmo/lxc