rex_job_control dies because Minion::Backend::File no longer exists

[mbroadhead]

rex_job_control dies because Minion::Backend::File no longer exists.
Minion::Backend::File was removed in Minion 3.0, see the Minion ChangeLog:

3.0 2015-10-30

• Removed Minion::Backend::File, because DBM::Deep quickly becomes unusably
  slow, you can use the CPAN module Minion::Backend::SQLite instead.

[ehuelsmann]

@mbroadhead this should have been resolved now. could you please verify and confirm? (Likely additional fixes are required; I'm working on that)