convert: fix history topology when using hg.tagsbranch When using hg.tagsbranch, all conversions fail at transcribing the source repo topology with conversion scenarios interleaving: - initial repo conversion, - then upstream tag - then later incremental conversion The problem is caused by the usage of the last source revid as source revid for the tagnode in the revision map. On a later incremental conversion, when resolving some child commit of the true last source revid, convert will parent the nodes to the tag node. If using tagsbranch you get a bad topology where all incremental commit nodes end up in the tag branch. Analysis and test by Edouard Gomez <ed.gomez@free.fr>