also, use http download instead of scp,
because scp won't work well on Windows.

BUG=chromium:113153
Review URL: https://chromiumcodereview.appspot.com/9369023

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@121820 0039d316-1c4b-4281-b951-d872f2087c98