Bug#1139437: firefox-esr: freezes after a bit on some sites, reproducer: media.autoplay.blocking_policy=2

[Thorsten Glaser]

forwarded 1139437 https://bugzilla.mozilla.org/show_bug.cgi?id=2045936
thanks

Note setting it to 1 also freezes the browser,
it must be 0 for it to work.