convert filter: supply path to external driver
Filtering to support keyword expansion may need the name of
the file being filtered. In particular, to support p4 keywords
like
$File: //depot/product/dir/script.sh $
the smudge filter needs to know the name of the file it is
smudging.
Allow "%f" in the custom filter command line specified in the
configuration. This will be substituted by the filename
inside a single-quote pair to be passed to the shell.
Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>