build_image: rollback default error behavior until kernel-next merge
build_image: rollback default error behavior until kernel-next merge

kernel-next lacks error mode 3.  Rolling back until merged.

TEST=none: rolling back to old value
BUG=chromium-os:8442

Change-Id: I0c1a89dc3e00fe5f315b3c15c5070209b0fd79d0

Review URL: http://codereview.chromium.org/4512004

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