Delete dead code in build_image relating to ESP_LOOP_DEV
Delete dead code in build_image relating to ESP_LOOP_DEV

BUG=None
TEST=build_image

Change-Id: I10aba40538e9c6aeaf803ffc50bb029dcf6d4be5
Reviewed-on: http://gerrit.chromium.org/gerrit/5009
Reviewed-by: Chris Sosa <959d3d631fb6f17f1b07f751372041a1edb210d1@chromium.org>
Tested-by: Richard Barnette <9e7d66387742bf40b0d2548ef2b93e7c522ca0eb@chromium.org>

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