unshare pidns and setns syscall

Hi Eric,

do you plan to send a new version of the 'setns' patchset ? I will be happy to test it if you have a more recent one.

In the meantime, we kept porting your patchset on top of the latest kernels.
http://lxc.sourceforge.net/patches/linux/2.6.35/2.6.35-lxc1/patches/

Thanks
-- Daniel