graft: always allow hg graft --base . (issue6248)...
graft: always allow hg graft --base . (issue6248)
`hg graft --base . -r abc` is rejected before this change with a
"nothing to merge" error, if `abc` does not descend from `.`.
This looks like an artifact of the implementation rather than intended
behavior. It makes perfect sense to apply the diff between `.` and
`abc` to the working copy (i.e. degenerate into `hg revert`),
regardless of what `abc` is.
Differential Revision:
https://phab.mercurial-scm.org/D8127
