bzip2: Update soname for libbz2 1.0.8

Set shared library name as libbz2.so.1.0.8, version in configure.ac
already synced via do_configure PV substitution.

Signed-off-by: Tom Pollard <tom.pollard@codethink.co.uk>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 07e3abc9)
Signed-off-by: Steve Sakoman <steve@sakoman.com>