Fixed build failure w/ new sudo
Fixed build failure w/ new sudo

Change-Id: I2760e33e1473ce04f7adeda39d0db5725eaa81ae

BUG=chromium-os:7072
TEST=Replaced ./build_packages with bash and ran command; valided env var set right.

Review URL: http://codereview.chromium.org/5930002

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