fix: uranus and saturn IP addresses

Mistake: Saturn referred to the NY node and vice versa.

Correction: Fittingly, Uranus is in NY and _S_aturn is _S_ingapore.

I'll have to reboot the testnet to rectify the changes.

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>
Merge pull request #431 from jbenet/hotfix/bootstrap-uranus-saturn

fix(bootstrap) swap IP addresses of Uranus and Saturn