Localhost selected from old settings which ought to return a non-local platform

[wxtim]

Describe the bug
The following config

# Part of suite.rc[runtime][<namespace>]
    [[remote]]
      host = my_hpcA
    [[job]]
      batch system = pbs

Is expected to select platform my_hpc - but instead selects localhost.

On inspection of the platform code it looks like OrderedDictWithDefaults does not over-ride the get method.

as a result the attempt to use

            task_job_section = task_conf.get("job", {})
            task_remote_section = task_conf.get("remote", {})

To retrieve the task job and task remote sections to be fed to the platform guessing function is returning {}.

Pull requests welcome!
This is an Open Source project - please consider contributing a bug fix
yourself (please read CONTRIBUTING.md before starting any work though).