Fix testing if fireCallback undefined in saveToBrowserStorage() 

In https://github.com/simsalabim/sisyphus/commit/0580ddcf09e1aeab2e415d2982390ebcfa92c6fc  this line https://github.com/simsalabim/sisyphus/commit/0580ddcf09e1aeab2e415d2982390ebcfa92c6fc#L0L352 was changed to https://github.com/simsalabim/sisyphus/commit/0580ddcf09e1aeab2e415d2982390ebcfa92c6fc#L0R343

This change will cause the onSave callback never be called if the timeout  is 0 and also cause the jasmine failed.