Fix re: and glob: patterns in .hgignore (reported by Brad Schick)
relglob: and relre: were already detected for a long time, so
I kept this undocumented functionality, especially as it was already
tested in test-hgignore.
Is there an error message when trying to diff non-existing files?
found: No such file or directory
not: No such file or directory
Is there an error message when trying to add non-existing files?
found: No such file or directory
not: No such file or directory