Hm, I think the real bug is the (<<
5.9.0) thing in libversion-perl. The
conflicts in perl-modules are designed to prevent an *earlier* version
of a separately packaged module to override a newer core version.
For instance, perl-modules conflicts with libmodule-build-perl
(<< 0.2808.1-1), because it contains 0.2808.1 itself. Installing the current
version of libmodule-build-perl on top of the current perl-modules isn't
broken, just useless.
The same would apply to libversion-perl without the (<<
5.9.0).
I suggest just having libversion-perl removed, it can always be
reintroduced if >0.7400 is ever released and somebody needs/wants it.
Similarly, libmodule-build-perl 0.2808.01 shouldn't be shipped with
lenny (but removing it from sid might be overkill because it's certainly
going to be updated upstream).
Stable has libversion-perl 0.6701-1, so the conflict in perl-modules
will take care of removing it on upgrades.
Sorry if I'm missing something.