specs: Define remote private image secret behavior
specs: Define remote private image secret behavior

Closes #381

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

stgraber/lxd,pcdummy/lxd,dvbportal/osx-lxd,ollie314/lxd,stgraber/lxd,basvanbeek/lxd,achanda/lxd,lxc/lxd,georghopp/lxd,yura-pakhuchiy/lxd,hallyn/lxd,sl1pm4t/lxd,atxwebs/lxd,techtonik/lxd,stgraber/lxd,mjeanson/lxd,ericsnowcurrently/lxd,smoser/lxd,Skarlso/lxd,chrisglass/lxd,stgraber/lxd,stgraber/lxd,Malizor/lxd,jensg-st/lxd,jsavikko/lxd,achanda/lxd,mikemccracken/lxd,benaryorg/lxd,hallyn/lxd,dustinkirkland/lxd,hallyn/lxd,stgraber/lxd,achanda/lxd,pcdummy/lxd,lxc/lxd,smoser/lxd,Malizor/lxd,tych0/lxd,ericsnowcurrently/lxd,erikmack/lxd,jensg-st/lxd,sl1pm4t/lxd,Skarlso/lxd,ollie314/lxd,erikmack/lxd,lxc/lxd,jumpstarter-io/lxd,techtonik/lxd,ericsnowcurrently/lxd,mikemccracken/lxd,sl1pm4t/lxd,hallyn/lxd,yura-pakhuchiy/lxd,atxwebs/lxd,chrisglass/lxd,jsavikko/lxd,atxwebs/lxd,jsavikko/lxd,pcdummy/lxd,dustinkirkland/lxd,dvbportal/osx-lxd,jumpstarter-io/lxd,ollie314/lxd,lxc/lxd,mjeanson/lxd,dustinkirkland/lxd,beni55/lxd,rcj4747/lxd,smoser/lxd,beni55/lxd,akshaykarle/lxd,Skarlso/lxd,akshaykarle/lxd,rrva/lxd,georghopp/lxd,rrva/lxd,beni55/lxd,benaryorg/lxd,rcj4747/lxd,erikmack/lxd,tych0/lxd,benaryorg/lxd,georghopp/lxd,jensg-st/lxd,lxc/lxd,Skarlso/lxd,basvanbeek/lxd,Malizor/lxd,tych0/lxd,basvanbeek/lxd,yura-pakhuchiy/lxd,hallyn/lxd,akshaykarle/lxd,techtonik/lxd,lxc/lxd,atxwebs/lxd,stgraber/lxd,mikemccracken/lxd,chrisglass/lxd,hallyn/lxd,lxc/lxd,jumpstarter-io/lxd,rcj4747/lxd,rrva/lxd,dvbportal/osx-lxd,mjeanson/lxd