confile: support 'lxc.include' option to include other config files
confile: support 'lxc.include' option to include other config files

For instance

lxc.include = /var/lib/lxc/commonopts

in /var/lib/lxc/q1/config would cause the configuration in
/var/lib/lxc/commonopts to be loaded when container q1 starts.

Signed-off-by: Serge Hallyn <3df611b026e4639bee8aef7a4beb2e39fcebb313@ubuntu.com>

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