The `OPT_FILENAME()` option will, if set, put an allocated string into
the user-provided variable. Consequently, that variable thus needs to be
free'd by the caller of `parse_options()`. Some callsites don't though
and thus leak memory. Fix those.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>