Comment 16 for bug 1504781

This seems to explain it, currently trying to teach myself apparmor to find a temporary fix...

apps kernel: [ 707.036112] audit: type=1400 audit(1445331859.865:41): apparmor="DENIED" operation="mount" info="failed type match" error=-13 profile="/usr/bin/lxc-start" name="/dev/ptmx" pid=2746 comm="lxc-start" srcname="/dev/pts/ptmx" flags="rw, bind"