Ignore packages that cannot be found for the target.
Ignore packages that cannot be found for the target.

Change-Id: I1b08fe7fe292605543579af0df358cb2fcbf0b97

BUG=
TEST=Ran it with dev-utils/crosutils

Review URL: http://codereview.chromium.org/5281001

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