Avoid to require non crossplatform packages

Change-Id: Icd8595d095a6ebd099235be158dcd16d92eb94b1
diff --git a/linux/system/single/rhel.yml b/linux/system/single/rhel.yml
new file mode 100644
index 0000000..38dba03
--- /dev/null
+++ b/linux/system/single/rhel.yml
@@ -0,0 +1,4 @@
+classes:
+- system.linux.system.single
+
+# RHEL family overrides