copies: distinguish between merged and touched files during upgrade This a filenode being different between p1, p2 and result does not necessarily means a merges happens. For example p2 could be a strict newer version of p1, so the p2 version is picked by the manifest merging, but then the file is manually updated before the commit. In this case the file should be detected as touched. Differential Revision: https://phab.mercurial-scm.org/D10220