- On high core, fast machines, jobs=8 is does not offer good
  parallelization.  Switch to use number of local cpus.

R=maruel@chromium.org
BUG=


Review URL: https://chromiumcodereview.appspot.com/11140019

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@162072 0039d316-1c4b-4281-b951-d872f2087c98