test: work around a bug in debugobsolete The defautl date was wrong all along. So we use a fixed date for all tests.

merge with stable

uncommit: add a --rev argument The uncommit command now taks a --rev argument. This lets restore the file content in the current commit to another revision (instead of just is parent content). This still does not touch the working directory content.\ This allow the longly awaited: hg uncommit --hidden --rev 'precursors(.)'