Always Show Errors, even if Upgrades Required

[brodieG]

Painted into a corner on CRAN:

  | The following unitizers will be upgraded to version '1.4.17':
  |
  | - unitizer/nchar.unitizer (at '1.4.14')
  | - unitizer/url.unitizer (at '1.4.14')
  
  Error in unitize_core(test.files = test.files, store.ids = store.ids, :
    Cannot proceed in non-interactive mode.
  Calls: unitize_dir -> unitize_core
  Execution halted

With no output. Need to make sure in non-interactive mode can proceed in a useful manner.