Add pref security.sri.enable (subresource integrity)
Add pref security.sri.enable (subresource integrity)

Added to Firefox in http://hg.mozilla.org/mozilla-central/rev/bab5913ea6cb

nth10sd/funfuzz,MozillaSecurity/funfuzz,MozillaSecurity/funfuzz,nth10sd/funfuzz,nth10sd/funfuzz,MozillaSecurity/funfuzz