grep: filter target files by matcher Prepares for the migration to logcmdutil's logic, where cmdutil.walkchangerevs() won't always build an exact set of paths to be scanned.

cmdutil: make walkchangerevs() call prepare with matcher instead of filenames Prepares for migrating walkchangerevs() to logcmdutil's logic, which provides matcher-based interface.

grep: add option for logcmdutil.makewalker() to not filter revs by file pats This is needed to implement "grep --all-files".