build_packages: drop native `emerge --info`
build_packages: drop native `emerge --info`

Posting the emerge info for the native build isn't terribly useful, so
just punt it to clean up the build output slightly.

BUG=None
TEST=`./build_packages --board=x86-alex` still works

Change-Id: If4ddb437b68c5624f3bc1a7519ef409134ba687b
Reviewed-on: https://gerrit.chromium.org/gerrit/26044
Reviewed-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Tested-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
Commit-Ready: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>

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