Can't run datadelivery service if arex is also configured in arc.conf

If [datastaging-delivery] and [arex] blocks are both present in arc.conf then arc-datadelivery-service tries to start both services. arched fails to start a-rex because of bad configuration but it should not try to start it at all.

[2018-04-26 14:19:38] [ERROR] [1531135/19227648] Plexer (plexer) - next ^/arex\(/\|$\)(a-rex) has no target

The reason it tries to start a-rex is because the general profile has

      <next id="a-rex" inisections="arex" initag="endpointpattern" initokenenables="arex" inidefaultvalue="^/arex\(/\|$\)"/>

One solution is to simply remove everything except datadelivery from the profile, since nothing else uses it.