Use --official_build boolean.
Use --official_build boolean.

Review URL: http://codereview.chromium.org/2843051

mjg59/scripts,vmware/coreos-scripts,mischief/scripts,coreos/scripts,bcwaldon/coreos-scripts,trnubo/scripts,zhang0137/scripts,endocode/scripts,andrejro/coreos--scripts,trnubo/scripts,smilart/scripts,smilart/scripts,glevand/coreos--scripts,zhang0137/scripts,gtank/scripts,marineam/coreos-scripts,endocode/scripts,mischief/scripts,fivethreeo/scripts,BugRoger/scripts,nicescale/scripts,sigma/coreos-scripts,vmware/coreos-scripts,sigma/coreos-scripts,nicescale/scripts,smilart/scripts,zhang0137/scripts,mischief/scripts,sigma/coreos-scripts,bcwaldon/coreos-scripts,mjg59/scripts,gtank/scripts,nicescale/scripts,andrejro/coreos--scripts,marineam/coreos-scripts,gtank/scripts,crawford/scripts,BugRoger/scripts,fivethreeo/scripts,BugRoger/scripts,andrejro/coreos--scripts,bcwaldon/coreos-scripts,coreos/scripts,glevand/coreos--scripts,endocode/scripts,crawford/scripts,fivethreeo/scripts,trnubo/scripts,mjg59/scripts,marineam/coreos-scripts,crawford/scripts,vmware/coreos-scripts