commitextras: fix on Python 3 by using sysstrs for __dict__ ops I'm dubious of the __dict__ shenanigans in use here, but lack the enthusiasm for figuring out why that was done right now. # skip-blame just some r prefixes Differential Revision: https://phab.mercurial-scm.org/D2435

util: use pycompat.bytestr() instead of str() This fixes at least some environment variable prints for util.system() callers on Python 3. Yay! Differential Revision: https://phab.mercurial-scm.org/D2434

showconfig: allow multiple section.name selectors (issue5797) This seems useful and we can disambiguate the output format solely by the type of the command arguments.