eol: cache needs update, also if it has same timestamp as the source
Ignoring same timestamp could (in theory?) cause changes to not be detected.
It might happen quite often that the cache is populated right after .hgeol has
been updated and they thus have the same time stamp second. But we want
correctness, and if it populates the cache so fast, then it can also not be a
big problem to run it again next time when the timestamp has moved on.