do not both fail and retry the job if it fails before perform

After forking, but before perform is called, the job will be scheduled
for retry, but will also bubble up to the failed queue.  A manual replay
at that point, could be disasterous.
wrap new behavior in env var

This is not permanent.  It's so I can turn this on only for some workers
and quickly turn it off, if needed
remove ENV check and add a verbose comment as to wtf is going on
code review cleanups

Also addresses an issue where the entire suite fails because the workers
are stateful across tests
oops, bad block syntax
spaces after commas
use a special-built job and avoid instance_variable_get
consistently format both redis accesses
Merge pull request #100 from stitchfix/handle-failures-before-perform

Do not both fail and retry the job if it fails before perform