fix 'convert' with single commit repositories
The attached patch passes the three 'convert' testcases, and also is
able to successfully convert the git.git repository.
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
warning: conflicts during merge.
merging a
merging a failed!
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
There are unresolved merges, you can redo the full merge using:
hg update -C 2
hg merge 1
e7fe8eb3e180+0d24b7662d3e+ tip
<<<<<<< my
something else
=======
something
>>>>>>> other
M a