Don't allow hardlinks in tarball.
Don't allow hardlinks in tarball.

These errors on extraction if you don't have the original targets
of the links on the image (i.e. if the stateful_partition gets wiped).

Change-Id: Id5d3f770830de6165613d506733c04edefccd3fb

BUG=chromium-os:9103
TEST=Ran update, wiped partition, ran stateful_update and ran bvt's.

Review URL: http://codereview.chromium.org/4882006

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