refresh_index: do not show unmerged path that is outside pathspec

refresh_index: do not show unmerged path that is outside pathspec

When running "git add --refresh <pathspec>", we incorrectly showed the
path that is unmerged even if it is outside the specified pathspec, even
though we did honor pathspec and refreshed only the paths that matched.

Note that this cange does not affect "git update-index --refresh"; for
hysterical raisins, it does not take a pathspec (it takes real paths) and
more importantly itss command line options are parsed and executed one by
one as they are encountered, so "git update-index --refresh foo" means
"first refresh the index, and then update the entry 'foo' by hashing the
contents in file 'foo'", not "refresh only entry 'foo'".

Signed-off-by: Junio C Hamano <gitster@pobox.com>