Propagate CHROMEOS_OFFICIAL into the environment for customize_rootfs.sh
Propagate CHROMEOS_OFFICIAL into the environment for customize_rootfs.sh

Review URL: http://chromereview.prom.corp.google.com/1176006

git-svn-id: 59a3318ba88c04536d83f47c63c52b7f675c4a1a@32 06c00378-0e64-4dae-be16-12b19f9950a1

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