Remove recently deprecated behavior

[cottsay]

Some recent changes to the buildfarm will break if the deployed Jenkins jobs are not in sync with the repository, so we'll need to make the changes in multiple stages. This issue tracks the follow-up stages of the changes so that the backwards-compatible changes aren't left in the code.

• Add os_name argument to check_sync_criteria #726 added the os_name argument to run_check_sync_criteria_job.py. That argument should be made required.
• Use directory arguments on deb job scripts for decoupling #769 changed the behavior of some directory arguments to facilitate decoupling. Those arguments should be made required or mapped in the scripts to become used as necessary.
  • Use directory arguments on deb job scripts for decoupling (Part Two) #709 is an intermediate change to start using the arguments modified in the first change
• Update repository status page to support RPM #781 modified an argument to pass the os_name. The old argument should be dropped. Additionally, an Ubuntu-specific wrapper function should be dropped from status_page.py.
• Introduce a PlatformPackageDescriptor object #785 introduced an object for storing platform-specific package metadata retrieved from a repository. That str-compatible object should be replaced with a namedtuple as described in the comments.
• [ ] Don't show subpackage source packages as missing #787 added an attribute to an existing namedtuple and was given a default value. That default should be dropped making the new attribute mandatory.
• Set trigger_timer from build file if unset. #922 deprecated a redundant function argument which should be removed.
• Deprecate unused dist_file kwarg from configure_ci_job #926 deprecated an unused function argument which should be removed.
• Don't configure CI maintenance job more than once #941 deprecated an unused function argument which should be removed.