setconf clears bridge descriptor refetch timers
I was looking at #2355 (moved)'s hopes of refetching bridge descriptors as soon as the bridge list changes. My plan was to simply call fetch_bridge_descriptors(now) from inside options_act() once we've cleared and reparsed the bridge lines.
Then I realized that clearing and reparsing the bridge lines resets the timers. So currently Tor clients that use bridges will refetch all their bridge descriptors an average of 30 seconds after each setconf. Bug.
Better behavior might be to leave parsed bridges alone if they're the same.