Set region in child process.

RegionedDeployer used to set the region for its consul object in its
constructor.  Since consuls are shared between objects, setting the
region at this point meant that all deployer objects would share the
region of the latest instantiated deployer.

This change pushes the region setting to a later time in the deployment
once the deployers have all been forked into their child processes.
This allows each deployer to set its own region.