convert/svn: keep latest and not oldest tag value

Don't use sed -r; instead use old-style regexp Rev d895158fe8af introduced some sed -r tests, but -r is only available on GNU sed, while BSD sed uses -E. Better to use old-style regular expressions, that way the tests work on all sed variants.

localrepo: Refactor var names in filecommit to improve readability.

merge with crew-stable I pushed the dd1b47e17d7e to crew before realizing that it would also be suitable for crew-stable, hence the double changeset.