build: Make enable_localaccount.sh skip outdated packages.
build: Make enable_localaccount.sh skip outdated packages.

This script would previously fail before getting to
make.conf.user if it couldn't access either of pam_google
and pam_offline.  Per cmasone, these packages are outdated
now and don't need to be updated.

BUG=none
TEST=ran the script

Change-Id: I5278c73562e580bdc90866c25c6b079b10b5e708

Review URL: http://codereview.chromium.org/3165039

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