cache files older than file are not ignored

[Peter Johansson]

I think there is a minor bug in the usage of cache files. The case is a bit of a corner case but still. Say that we have a file, foo.txt with some history at rev 101. We run svndigest and a cache file is created rflecting the state at rev 101. Then we delete the foo.txt, but the cache file will still be around. Then a new file foo.txt is created with its own history. Next time we run svndigest I suspect that the old cache file will interfere and the screw up things a bit.

We should investigate what really happens, but it seems a reasonable solution to ignore cache files that are older than the file itself (older means wrt to rev not time-stamp)

[Peter Johansson]

The situation is a bit better with #510 implemented but problem is not solved so I keep this ticket open.