Log Message:
py-mercurial: update to 6.5.3.

Mercurial 6.5.3

    "hgweb: pass strings in WSGI environment correctly from wsgicgi"
    "perf: introduce more cache invalidation option in perf::tags"
    "perf: add a --clear-fnode-cache-rev argument to perf::tags"
    "perf: add a --update-last flag to perf::tags"
    "blackbox: add a option to duplicate output to stderr too"
    "tags: avoid expensive access to repo.changelog in a loop"
    "revlog: fix a bug where NULL_NODE failed to be resolved to NULL_REV"
    "httppeer: fix static-http: scheme autodetection (issue6833)"
    "tests: backed out changeset 8037ddacad47"
    "stream-clone: fix a crash when a repo with an empty revlog is cloned"
    "censor: accept censored revision during upgrade"
    "revlog: avoid opening and closing the file for each cloned revision"