lxc_map_ids: add a comment
lxc_map_ids: add a comment

Explain why we insist that root use newuidmap if it is available.

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

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