nodemap: delete older raw data file when creating a new ones When we write new full files, it replace an older one with a different name. We add the associated cleanup for the older file to be removed after the transaction. We delete all file matching the expected pattern to give use extra chance to delete orphan files we might have failed to delete earlier. Note: eventually we won't rewrite all data for each transaction. This is coming in later changesets. Differential Revision: https://phab.mercurial-scm.org/D7839