Log Message:
Update to 31.4.0

Changelog:
Fixed in Firefox ESR 31.4

    2015-06 Read-after-free in WebRTC
    2015-04 Cookie injection through Proxy Authenticate responses
    2015-03 sendBeacon requests lack an Origin header
    2015-01 Miscellaneous memory safety hazards (rv:35.0 / rv:31.4)