fix btrfs_recursive_destroy
fix btrfs_recursive_destroy

A change in kernel 4.2 caused btrfs_recursive_destroy to
fail to delete unprivileged containers.  This patch restores
the pre-kernel-4.2 behaviour.  Ref: Issue 935.

Signed-off-by: Oleg Freedhom <59b555c821c52d7a36ae312eec76a1429194a15d@gmail.com>

GreatFruitOmsk/lxc,LynxChaus/lxc,LynxChaus/lxc,ss1h2a3tw/lxc,hallyn/lxc,QingweiPeterLan/cs188-lxc,caglar10ur/lxc,akshaykarle/lxc,caglar10ur/lxc,hfuCN/lxc,thmo/lxc,federicobriata/lxc,GreatFruitOmsk/lxc,thmo/lxc,ss1h2a3tw/lxc,hallyn/lxc,ss1h2a3tw/lxc,terceiro/lxc,QingweiPeterLan/cs188-lxc,terceiro/lxc,terceiro/lxc,akshaykarle/lxc,ysbnim/lxc,caglar10ur/lxc,ysbnim/lxc,federicobriata/lxc,aeris/lxc,aeris/lxc,akshaykarle/lxc,hallyn/lxc,thmo/lxc,QingweiPeterLan/cs188-lxc,hfuCN/lxc,ysbnim/lxc,cjwatson/lxc,LynxChaus/lxc,aeris/lxc,federicobriata/lxc,cjwatson/lxc,cjwatson/lxc,hfuCN/lxc,GreatFruitOmsk/lxc