lxc-download: Fix undefined DOWNLOAD_FORCE_CACHE
lxc-download: Fix undefined DOWNLOAD_FORCE_CACHE

Signed-off-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>
Acked-by: Serge E. Hallyn <3df611b026e4639bee8aef7a4beb2e39fcebb313@ubuntu.com>

major/lxc,rowhit/lxc,caglar10ur/lxc,Distrotech/lxc,jirislaby/lxc,efiop/lxc,ysbnim/lxc,ss1h2a3tw/lxc,terceiro/lxc,ojkastl/lxc_Patches,JohnPeacockMessageSystems/lxc,aeris/lxc,terceiro/lxc,Distrotech/lxc,bmoar/lxc,yubo/lxc,LynxChaus/lxc,ss1h2a3tw/lxc,hkjolhede/lxc,tych0/lxc,regit/lxc,JohnPeacockMessageSystems/lxc,aeris/lxc,szaszg/lxc,ysbnim/lxc,weizhenwei/lxc,virajs/lxc,ojkastl/lxc_Patches,thmo/lxc,lisongmin/lxc,QingweiPeterLan/cs188-lxc,bmoar/lxc,Pelagicore/lxc,weizhenwei/lxc,christiaan/lxc,lisongmin/lxc,hallyn/lxc,JohnPeacockMessageSystems/lxc,caglar10ur/lxc,Ponce/lxc,fwilson42/lxc,rldleblanc/lxc,caglar10ur/lxc,hkjolhede/lxc,GreatFruitOmsk/lxc,lazy404/lxc,ksperis/lxc,virajs/lxc,sapun/lxc,armcc/lxc,rldleblanc/lxc,cjwatson/lxc,lazy404/lxc,raspberrypython/lxc,fwilson42/lxc,jirislaby/lxc,efiop/lxc,tych0/lxc,LynxChaus/lxc,lisongmin/lxc,bostjan/lxc,ysbnim/lxc,hfuCN/lxc,ioops/lxc,akshaykarle/lxc,aeris/lxc,akshaykarle/lxc,codebauss/lxc,DarknessBeforeDawn/lxc,regit/lxc,federicobriata/lxc,GreatFruitOmsk/lxc,Pelagicore/lxc,weizhenwei/lxc,rowhit/lxc,sapun/lxc,yubo/lxc,ecarrara/lxc,LynxChaus/lxc,ecarrara/lxc,rldleblanc/lxc,thmo/lxc,cjwatson/lxc,hallyn/lxc,Ponce/lxc,christiaan/lxc,szaszg/lxc,GreatFruitOmsk/lxc,terceiro/lxc,ioops/lxc,Pelagicore/lxc,codebauss/lxc,regit/lxc,armcc/lxc,ksperis/lxc,tych0/lxc,DarknessBeforeDawn/lxc,thmo/lxc,QingweiPeterLan/cs188-lxc,fwilson42/lxc,major/lxc,Ponce/lxc,bostjan/lxc,hallyn/lxc,bmoar/lxc,yubo/lxc,federicobriata/lxc,hfuCN/lxc,rowhit/lxc,szaszg/lxc,ss1h2a3tw/lxc,ioops/lxc,christiaan/lxc,ecarrara/lxc,hfuCN/lxc,efiop/lxc,bostjan/lxc,major/lxc,DarknessBeforeDawn/lxc,lazy404/lxc,hkjolhede/lxc,raspberrypython/lxc,virajs/lxc,QingweiPeterLan/cs188-lxc,federicobriata/lxc,sapun/lxc,akshaykarle/lxc,raspberrypython/lxc,ojkastl/lxc_Patches,ksperis/lxc,ojkastl/lxc_Patches,jirislaby/lxc,cjwatson/lxc,Distrotech/lxc,codebauss/lxc,armcc/lxc