convert: handle past or foreign partial svn copies
Subversion allows revisions to be composed of subparts coming from revisions
before the parent or from other part of the repository. There is no simple
representation for these now, keep the changes but do not track their origins.
a
b/a
l
644 a
755 * b/a
644 @ l
b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644 a
b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 755 * b/a
047b75c6d7a3ef6a2243bd0e99f94f6ea6683597 644 @ l
a
l
a
b/a
l
a
b/a
l
% should fail
abort: unknown revision '2'!
abort: please specify just one revision
a
b/a
l