lxc-attach: use execvp instead of execve
lxc-attach: use execvp instead of execve

execvp does not require specifying the full path to the executable
(e.g., "ls" instead of "/bin/ls"), making the operation of 'lxc-attach'
consistent with 'lxc-start' and 'lxc-execute'.

Signed-off-by: David Ward <6be1308aeebeeeac115bb2fe2e0d71ae5645edd9@ll.mit.edu>
Signed-off-by: Daniel Lezcano <3211518dd4d87cb3f7ee12cb52e14b7fb2bc0446@fr.ibm.com>

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