narrow: move requirement constant to core My short-term goal is to move narrowrepo.narrowmatch() onto localrepo and this is a necessary step for that. I put the constant in changegroup.py, unlike REVLOGV2_REQUIREMENT, which is in localrepo.py, since we'll need to access it from the changegroup module eventually. Differential Revision: https://phab.mercurial-scm.org/D2487

remotenames: don't inherit the remotenames class from dict class The remotenames class was moved from hgremotenames extension. The class in hgremotenames extension used to extend dict because updating bookmark was done through a dict-like interface or Sean (smf) wanted it to be that way. But now, we can remove the inheritance from the dict class as updating bookmark is not done using a dict-like interface. Thanks to Martin von Zweigbergk for spotting this. Differential Revision: https://phab.mercurial-scm.org/D2361