bundle: warn when update to revision existing only in a bundle (issue5004) Now its done silently, so unless user really knows what he is doing will be suprised to find that after update 'hg status' doesn't work. This commit makes also merge operation warns about missing parent when revision to merge exists only in the bundle.

tests: fix builtin module test on pypy On pypy datetime and cProfile are modules written in Python, not in C. For the purpose of this test, just list them explicitely as builtins, which silences warnings about them being imported before stdlib modules.

hgweb: generate last change date for an empty atom-bookmarks feed (issue5022) RFC 4287 states that atom feeds must have an <updated> element, so let's add one even when repo doesn't have a single bookmark.