Sort all fingerprints in rejection/middleonly etc. rules including those for relays not found by margot

Sometimes in a fingerprint file passed to margot there could be fingerprints of relays which margot does not know anything about (be it those relays are actually not running or there are bugs like #32). It seems that margot does not sort fingerprints for rejection properly for those instances. For instance, I just saw a stanza where we ended up with

+!reject EC3C600752BB80C7852EC6FE9163AD10B95BC2B3
+!reject EEC1D873B5640D8239D773BF633A2F45E98EEA5B
+!reject 56A4643CF471F59D63568563D66A21229898537C

Where 56A4643CF471F59D63568563D66A21229898537C was the only fingerprint in that group that belonged to a relay margot thought was not running.