Correct docstring for contrail.global_vrouter_config_create function

Change-Id: I1463f9adeccd9103417cd7c1f4441179858305b7
Related-PROD: PROD-27854
diff --git a/_modules/contrail.py b/_modules/contrail.py
index 46c23f7..8374dd3 100644
--- a/_modules/contrail.py
+++ b/_modules/contrail.py
@@ -733,7 +733,11 @@
 
     .. code-block:: bash
 
-        salt '*' contrail.global_vrouter_config_create name=global-vrouter-config parent_type=global-system-config encap_priority="MPLSoUDP,MPLSoGRE" vxlan_vn_id_mode="automatic" fq_names="['default-global-system-config', 'default-global-vrouter-config']"
+        salt '*' contrail.global_vrouter_config_create \
+        name=global-vrouter-config parent_type=global-system-config \
+        encap_priority="MPLSoUDP,MPLSoGRE" vxlan_vn_id_mode="automatic" \
+        flow_export_rate=None \
+        fq_names="['default-global-system-config', 'default-global-vrouter-config']"
     '''
     ret = {'name': name,
            'changes': {},