test: Better fix LXD_DEBUG
test: Better fix LXD_DEBUG

The previous change didn't really work due to internal function calls.
Instead, lets just focus on silencing things once we hit a failure.

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

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