dirstate.remove: during merges, remember the previous file state
We encode the previous state as a negative file size (AFAICS, previous
versions of hg always have size == 0 when state == 'r').
We save the state of 'm'erged and dirty files, because they're the
two states that indicate that a file has to be committed on a merge
to correctly record per-file history.
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