Rotate default obfs4 bridges again

Link: ​https://lists.torproject.org/pipermail/tor-project/2016-August/000664.html

We would like to rotate the ports again for the next release. The previous ports will remain open and functional.

This is the second rotation, first one can be seen in ticket # 20092 here: https://trac.torproject.org/projects/tor/ticket/20092

Trac:
Username: lynntsai