Fix for go 1.4 build compat
Fix for go 1.4 build compat

normanjoyner/cadvisor,dchen1107/cadvisor,carmark/cadvisor,linux-on-ibm-z/cadvisor,f0/cadvisor,f0/cadvisor,datawisesystems/cadvisor,f0/cadvisor,vishh/cadvisor,ainsleyc/cadvisor,jhjeong-kr/cadvisor,timstclair/cadvisor,f0/cadvisor,ncdc/cadvisor,vishh/cadvisor,feiskyer/cadvisor,f0/cadvisor,dchen1107/cadvisor,shilpamayanna/cadvisor,timstclair/cadvisor,feiskyer/cadvisor,timstclair/cadvisor,ainsleyc/cadvisor,pwittrock/cadvisor,BrickXu/cadvisor,jhjeong-kr/cadvisor,BrickXu/cadvisor,linux-on-ibm-z/cadvisor,pwittrock/cadvisor,BrickXu/cadvisor,shilpamayanna/cadvisor,feiskyer/cadvisor,derekwaynecarr/cadvisor,erSitzt/cadvisor,jhjeong-kr/cadvisor,IFTTT/cadvisor,derekwaynecarr/cadvisor,guoshimin/cadvisor,BrickXu/cadvisor,IFTTT/cadvisor,normanjoyner/cadvisor,guoshimin/cadvisor,IFTTT/cadvisor,ncdc/cadvisor,jhjeong-kr/cadvisor,derekwaynecarr/cadvisor,ncdc/cadvisor,ainsleyc/cadvisor,erSitzt/cadvisor,dchen1107/cadvisor,linux-on-ibm-z/cadvisor,datawisesystems/cadvisor,carmark/cadvisor,derekwaynecarr/cadvisor,erSitzt/cadvisor,ainsleyc/cadvisor,erSitzt/cadvisor,dchen1107/cadvisor,ncdc/cadvisor,IFTTT/cadvisor,BrickXu/cadvisor,erSitzt/cadvisor,dchen1107/cadvisor,IFTTT/cadvisor,ncdc/cadvisor,jhjeong-kr/cadvisor,vishh/cadvisor,guoshimin/cadvisor,derekwaynecarr/cadvisor,pwittrock/cadvisor