Set strategy for judgehost deployment

Ansible has multiple strategies, the free strategy allowes each host to
run the tasks on their own speed. This means that already provisioned
hosts can already go to the next task while a new machine is still
applying a task.

Also fix comment as the next group only starts when the last one is
done.

Author: vmcj

provision-contest/ansible/judgehost.yml

@@ -3,11 +3,12 @@
 
 - name: setup judgehost
   hosts: judgehost
-  # We always leave 1/3 of the judges online
+  # We always leave 2/3 of the judges online
   serial:
     - 33%
     - 33%
     - 34%
+  strategy: free
   vars:
     host_type: judgehost
   become: true