recovery: do not create empty /var on stateful partition
recovery: do not create empty /var on stateful partition

The /var directory on the stateful partition is no longer used in the
recovery image, so there is no reason to mkdir it here.

BUG=chromium-os:32774
TEST=parrot and lumpy recovery image build, manual testing

Change-Id: I9ad936943e88cd2c8cb96a6f715f778c5c65d701
Signed-off-by: Kees Cook <50cb10d2be062154b17ab4d66a4eab34f1cf1c84@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/30488
Reviewed-by: Richard Barnette <9e7d66387742bf40b0d2548ef2b93e7c522ca0eb@chromium.org>

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