convert: clear the dirstate before a conversion, invalidate it afterwards
Clearing it before the conversion protects us from whatever data were
there (file copies in particular).
Invalidating it after the conversion avoids writing a possibly
inconsistent dirstate to disk.
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
removing b
abort: update spans branches, use 'hg merge' or 'hg update -C' to lose changes