Avoid running chef automatically

teuthology --lock formerly automatically ran chef on startup of
virtual machines. This covered up a bug where ceph-deploy would
not install properly. These changes remove the automatic running
of chef, and fixed some related issues when setting up keys on
virtual machines.

Fixes 9318:
Signed-off-by: Warren Usui <warren.usui@inktank.com>
Merge pull request #326 from ceph/wip-9318-wusui

Avoid running chef automatically.