[yum] call rhsm-debug with --no-subscriptions

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
[powerpc] allow PowerPC plugin to run on ppc64le

The plugin currently tests whether policy().get_arch() is equal
to "ppc64". On little endian PowerPC machines this method returns
"ppc64le". Change the check_enabled() method to test whether the
returned string contains "ppc64".

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>