[sailfish-browser] Fix backup. Contributes to JB#52318
[sailfish-browser] Fix backup. Contributes to JB#52318

This only fixes backing up. Older backups can not be restored correctly
with this change.

Signed-off-by: Tomi Leppänen <5c72ffe736be5009d7fd5b3f191ca04ec28863e0@jolla.com>

sailfishos/sailfish-browser,sailfishos/sailfish-browser,sailfishos/sailfish-browser,sailfishos/sailfish-browser,sailfishos/sailfish-browser