When a user tried to remove a policy module with priority other than 400 via
GUI, it failed with a message:
libsemanage.semanage_direct_remove_key: Unable to remove module somemodule at priority 400. (No such file or directory).
This is fixed by calling "semodule -x PRIORITY -r NAME" instead of
"semodule -r NAME".
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1740936
