lib/package_manager/ipk: Do not hardcode payload compression algorithm

The chosen payload compression algorithm can be changed by overriding
`OPKGBUILDCMD`. Ensure that package extraction deals with this by
globbing for "data.tar.*" to select the actual payload tarball.

Signed-off-by: Philip Lorenz <philip.lorenz@bmw.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 2ad05635)
Signed-off-by: Steve Sakoman <steve@sakoman.com>