backout: migrate `opts` to native kwargs
It will take a bit to unwind `cmdutil.commit`, so there's a conversion to
byteskwargs there, without changing the type of `opts` in this function. That's
also useful to flag it as needing to be changed.
#require symlink
https://bz.mercurial-scm.org/1438
$ hg init repo
$ cd repo
$ ln -s foo link
$ hg add link
$ hg ci -mbad link
$ hg rm link
$ hg ci -mok
$ hg diff -g -r 0:1 > bad.patch
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --no-commit bad.patch
applying bad.patch
$ hg status
R link
? bad.patch