Remove ltp from set of tests to build.
Remove ltp from set of tests to build.

The ltp tests don't pass, and take a long time to build. Once they pass,
it'll make sense to add them back. But otherwise, no point waiting for their
long build process to complete.

BUG=none
TEST=Run build_packages --withautotest

Review URL: http://codereview.chromium.org/3121010

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