Fixing indent and make nautilus script python3 compatible.

Make nautilus script python3 compatible. Please keep in mind, that you set the header to /usr/bin/python3, so it should be valid python3 code inside :)

python3 don't like tabs+spaces mixed up:
TabError: inconsistent use of tabs and spaces in indentation (syncstate.py, line 44)

and **except Exception,e** is no valid python3 code, the correct one is **except Exception as e**