Refactor choose_good_entry_server so it is (almost) never used
View options
From my prop271 branch:
* XXXX prop271 this function is used in four ways: picking out guards for
* the old (pre-prop271) guard algorithm; picking out guards for circuits;
* picking out guards for testing circuits on non-bridgees;
* picking out entries when entry guards are disabled. These options
* should be disentangled.