Clarify container delete failure error
Clarify container delete failure error

Signed-off-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>

hallyn/lxd,akshaykarle/lxd,lxc/lxd,georghopp/lxd,lxc/lxd,lxc/lxd,techtonik/lxd,hallyn/lxd,atxwebs/lxd,lxc/lxd,jsavikko/lxd,mjeanson/lxd,hallyn/lxd,erikmack/lxd,Skarlso/lxd,stgraber/lxd,pcdummy/lxd,Skarlso/lxd,techtonik/lxd,pcdummy/lxd,stgraber/lxd,chrisglass/lxd,jsavikko/lxd,hallyn/lxd,lxc/lxd,Skarlso/lxd,erikmack/lxd,techtonik/lxd,chrisglass/lxd,atxwebs/lxd,mjeanson/lxd,stgraber/lxd,mjeanson/lxd,jsavikko/lxd,chrisglass/lxd,atxwebs/lxd,lxc/lxd,stgraber/lxd,stgraber/lxd,hallyn/lxd,stgraber/lxd,georghopp/lxd,lxc/lxd,georghopp/lxd,stgraber/lxd,hallyn/lxd,Skarlso/lxd,akshaykarle/lxd,akshaykarle/lxd,erikmack/lxd,pcdummy/lxd,atxwebs/lxd