Modify Capistrano to work with zero-downtime deployments (TORQUE-1121)

Just tell Capistrano to use the current path symlink instead of the
latest release's actual path.
Disable management API/UI authentication for slim [TORQUE-1123]
Better zero-downtime deploys of shared pools (TORQUE-1124)

Shared pools will now wait for the new runtime to spin up before
pulling the old runtime out of the pool. We need to do the same for
bounded pool.