Fix process naming not working on actiivty workers and deciders
Fix process naming not working on actiivty workers and deciders

On activity workers it was raising an exception, and on deciders it was
setting the process name to a representation of the SWF "domain", which
is not the mot useful indication, because region and domain are likely
known in advance on a given machine (?). It's more useful to have the
kind of worker/poller and the task list involved.

botify-labs/simpleflow,botify-labs/simpleflow