wireprotov2: stop sending phase updates for base revisions This feature is broken and doesn't work properly in all scenarios. e.g. if we have the following DAGs: client server D draft C draft C draft B draft B public A public A public The current code would only send the phase data for C. The client wouldn't see that B moved from draft to public. This feature will be restored in a future commit. For now, it is making refactoring of how revisions are specified in the wire protocol a bit difficult... Differential Revision: https://phab.mercurial-scm.org/D4978