Fix circular structure typeerror in chromium(38)

The variable ```params``` contains the member ```obj``` which does not seem to be of interest by the server. In chromium, this obj - member leads to an ```Uncaught TypeError: Converting circular structure to JSON``` when calling ```JSON.stringify``` for ```params``` in the ```storage.patchContact(...)``` function. There might be some other points within the code with the same problem, but I didn't find any on the fly.