Add a cold-boot.sh script for the EWS

Add a cold-boot.sh script for the EWS
https://bugs.webkit.org/show_bug.cgi?id=90330

Unreviewed.

* EWSTools/cold-boot.sh: Added.
    - This script can take us from a cold GCE instance to a running EWS
      bot in one fell swoop.
* EWSTools/start-queue.sh:
    - The if-block at the top of this script was causing trouble. I
      removed it from the bots a while ago. Now that we're using SVN to
      cold-boot the EWS bots, we need to make this change in the repo.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@121621 268f45cc-cd09-0410-ab3c-d52691b4dbfc