Make `spreadsheet_root` a constant and add more of the URL to it
Fix #N/A sporadically appearing in the agency number widgets

- This was caused by Google Spreadsheets running the command to
  import data from the transition spreadsheet and not getting data.
  This made `#N/A` appear for unpredictable lengths of time,
  unpredictably, so this hopefully successfully deals with it by
  querying the spreadsheet every two seconds until the todo and done
  values are no longer `#N/A`, or another variant `#VALUE!`.
Remove some duplication in fetching org status
Fix undefined method error when running the org_status job

- This was caused by the `done` variable having been replaced with
  `value`.
Merge pull request #6 from alphagov/fix_na_appearing_on_agency_number_widgets

Fix #N/A appearing on agency number widgets