runtime/cases/smart.py: Check for IMAGE_PKGTYPE instead of PACKAGE_CLASSES
smart test requires to build the image using rpm packages, this check was
included, but it checked for PACKAGE_CLASSES=='package_rpm', and this is
not true when building packages for rpm and deb/ipk. So this would check
IMAGE_PKGTYPE instead.
[YOCTO #10964]
Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
