i18n: drop a py25 conditional I'm not sure how to test this one. `make update-pot` spews all kinds of warnings, though it did before this change too.

perf: ensure HGRCPATH is exported on Windows After dropping the garbage collector hack, `hg perfstartup` started yelling about not being able to import the evolve extension, which I have in my user config. Launching `env` shows that an empty HGRCPATH isn't exported to the environment. Since `env` doesn't quote, I have no idea if the variable is trimmed, but Mercurial doesn't complain when processing it.