We have libxml2-python for native and nativesdk, but don't have it for
target, and can't find the reason from the git log, libxml2-python is
widely used, after looked into it's configure.in, we can add it
by PACKAGECONFIG.
The previous --with-python=${STAGING_BINDIR}/python is incorrect, it
acted as work becase it's conigure can check automatically, python is in
${STAGING_BINDIR_NATIVE}/${PYTHON_PN}-native/${PYTHON_PN}, as known as
${PYTHON}.
Add python to PACKAGECONFIG, since createrepo rdepends on
libxml2-python, otherwise the target createrepo can't work.
Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
