fix log appending to any file
fix log appending to any file

With the capabilities, the open of the log file can be done on any
file, making possible to modifify the content of the file.

Let's drop the privilege when opening the file, so we ensure that is
no longer possible.

Signed-off-by: Daniel Lezcano <3211518dd4d87cb3f7ee12cb52e14b7fb2bc0446@fr.ibm.com>

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