Igor Sereda <sereda{__AT__}gmail.com> suggested on the dev@ list that
'svndumpfilter include/exclude --drop-empty-revs' should actually drop all empty
revisions (those that make no path modifications), rather than merely dropping
the revisions made empty by the filtering done by the current invocation of
svndumpfilter itself.
This would allow admins to purge empty revisions from repositories previously
populated by 'svndumpfilter' when --drop-empty-revs was not provided, or by
partial-repository mirroring via 'svnsync', etc.
Improvement
Major