Don't do yum check if installing from yum, due to lock clash

package-updates/postinstall.pl

@@ -6,7 +6,9 @@ sub module_install
 # Force clear all caches, as collected information may have changed
 &flush_package_caches();
 
-# Re-generate cache of available packages
-&list_available();
+if ($software::update_system ne 'yum') {
+	# Re-generate cache of available packages
+	&list_available();
+	}
 }