libarchive: enable non-recursive extract/list

libarchive: enable non-recursive extract/list

Required for meta-swupd performance enhancements: in meta-swupd, the
so called "mega" image contains a rootfs with all files that can
potentially be installed on a device. Other virtual image recipes need
a subset of those files or directories, and a partial extraction from
a single tar archive is faster than letting all virtual image recipes
share access to a directory under a single pseudo instance.

It may be necessary to extract a directory with all of its attributes
without the content of the directory, hence this patch. Upstream
agreed to consider merging such a patch (see
https://groups.google.com/forum/#!topic/libarchive-discuss/JO3hqSaAVfs)
but has been slow in actually commenting on it, so for now it has
to be carried as distro patch.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>