Bridges sharing the same IP should have the same bridge distribution method

In the last 'Run a bridge' campaign, Meskio and arma pointed out that having bridges sharing the same IP but using different ports would increase the probability of a censor to discover and block the bridge IP. As the censors are most likely blocking bridges by IP and not IP:Port, bridgeDB/rdsys should attribute the same bridge distribution method for bridges with the same IP.

Example: these new bridges are sharing the same IP but were automatically attributed two different distribution methods (settings, moat).