ipaplatform: Add constants submodule

Introduce a ipaplatform/constants.py file to store platform related
constants, which are not paths.

Reviewed-By: Martin Basti <mbasti@redhat.com>
Reviewed-By: Petr Spacek <pspacek@redhat.com>

ipaplatform/rhel/constants.py

@@ -0,0 +1,16 @@
+#
+# Copyright (C) 2015  FreeIPA Contributors see COPYING for license
+#
+
+'''
+This RHEL base platform module exports platform related constants.
+'''
+
+# Fallback to default constant definitions
+from ipaplatform.redhat.constants import RedHatConstantsNamespace
+
+
+class RHELConstantsNamespace(RedHatConstantsNamespace):
+    pass
+
+constants = RHELConstantsNamespace()