Update Chef to 12.5.1
Upgrading Chef to 12.5.1 for 'Chef.event_handler'.
This would allow us to run Chef handlers when certain events happen during a 'reconfigure' run. Upgrading to 12.5 also means that we don't need to include and ship the 'chef_handler' cookbook, which provides some (but not all) of the functionality from this upgrade.
@marin - any chance you could take a look at this?