rebase: catch RepoLookupError at restoring rebase state for abort/continue Before this patch, "rebase --abort"/"--continue" may fail, when rebase state is inconsistent: for example, the root of rebase destination revisions recorded in rebase state file is already stripped manually. Mercurial earlier than 2.7 allows users to do anything other than starting new rebase, even though current rebase is not finished or aborted yet. So, such inconsistent rebase states may be left and forgotten in repositories. This patch catches RepoLookupError at restoring rebase state for abort/continue, and treat such state as "broken".