chore($sniffer): Remove $sniffer.hashchange

The hashchange event is not supported only in ancient browsers like Android<2.2
and IE<8. Angular never really supported IE7 and in 1.3 where support for IE8
is dropped it makes even less sense to check for hashchange support.
IWO `This` in `This is still needed for ngCookies` referred to `$browser.addPollFn`, not the part removed here.