[sailfish-browser] Update for custom user agent. Contributes to JB#8552
[sailfish-browser] Update for custom user agent. Contributes to JB#8552

rojkov/sailfish-browser,alinelena/sailfish-browser,sailfishos/sailfish-browser,alinelena/sailfish-browser,sailfishos/sailfish-browser,sailfishos/sailfish-browser,rojkov/sailfish-browser,alinelena/sailfish-browser,sailfishos/sailfish-browser,alinelena/sailfish-browser,rojkov/sailfish-browser,sailfishos/sailfish-browser