Use PM_SU_CMD for pkg set -o

Reported by:	Anton Yuzhaninov

portmaster

@@ -4317,7 +4317,7 @@ if [ -z "$use_pkgng" ]; then
 else
 	if [ -n "$ro_opd" ]; then
 		echo "===>>> Updating dependency entry for $new_port in each dependent port"
-		pkg set -yo $ro_opd:$portdir
+		$PM_SU_CMD pkg set -yo $ro_opd:$portdir
 	fi
 fi