We were only setting LANGUAGE, but that does not set LC_TIME so the time was still
set to the "user" locale, we now set LC_ALL to switch the application completely to that language
Note we are not actually switching the posix locale, just all the
QLocale/ki18n related internals, strftime would still use the user
original locale. This is also the reason we don't really need to pass a
valid locale name to LC_ALL (i.e. we're giving it "ru" instead of
"ru_RU.UTF-8"), since the only thing we need to do is convince QSystemLocaleData::readEnvironment
and giving it "ru" is enough