rebase: avoid defining two lists with the same contents In abort(), there's "dstates" and "rebased" that are identical, which they seem to have been since 0806823370d8 (rebase: properly calculate descendant set when aborting (issue3332), 2012-03-22). Let's de-duplicate. I don't know what "dstates" means, but "rebased" makes sense (it's the list of rebased revisions), so let's pick that. Differential Revision: https://phab.mercurial-scm.org/D2878