Smart proxy dynflow core service failed with DSL error on Red Hat Satellite server.

Issue

• The satellite-installer command failed due to DSL error encountered for smart_proxy_dynflow_core service on Red Hat satellite server CLI:

  /Stage[main]/Foreman_proxy::Plugin::Dynflow/Service[smart_proxy_dynflow_core]/ensure: change from 'stopped' to 'running' failed: Systemd 
  start for smart_proxy_dynflow_core failed!
  journalctl log for smart_proxy_dynflow_core:
  -- Logs begin at Fri 2020-01-10 10:33:26 CET, end at Wed 2020-01-15 18:21:23 CET. --
  Jan 15 18:21:22 testing systemd[1]: Starting Foreman smart proxy dynflow core service...
  Jan 15 18:21:23 testing smart_proxy_dynflow_core[62198]: /opt/rh/rh-ruby25/root/usr/share/gems/gems/bundler-1.16.1/lib/bundler.rb:508:in `rescue in eval_gemspec': 
  Bundler::Dsl::DSLError