Reading the user and date information from graftstate during `hg graft
--continue` will help us in preserving the user and date arguments passed when
hg graft was called. This patch reads that information and reuses that while
running hg graft --continue. So after this patch, --user and --date values are
preserved even if conflicts occur and user don't need to pass them again.
The test changes demonstrate the fix.
This is a backward incompatible change but I think of this more as a bug fix.
Also thinking about removing the line from hg help graft which says --continue
does not reapply other flags but need to check what are the other flags which
needs to be preserved.