Revert "6362: Allow config/application.yml to override environments/*.rb in apiserver...

Revert "6362: Allow config/application.yml to override environments/*.rb in apiserver, too."

In Rails 3 (actionpack 3.2.17), changing asset configuration to
production settings in load_config.rb breaks the rake
assets:precompile task, e.g., the docker build. This change is still
desired but needs to be backed out until the bugs are worked out.

This reverts commit c790738ae71771a5574b166b3e93a1bca9b89bf6.

refs #6362