Manage upstream removal of nsLocaleService
Manage upstream removal of nsLocaleService

nsLocaleService was removed in Firefox 57, breaking our own
language service:
  https://bugzilla.mozilla.org/show_bug.cgi?id=1356263

Their upstream replacement, used in this patch, landed in Fx 54:
  https://bugzilla.mozilla.org/show_bug.cgi?id=1333184

nohamelin/simple-locale-switcher