Add available params in metering labels client's comment

Some interfaces in metering labels client have **kwargs parameter, but no
api reference links are given. so this is to add "Available params" in their
comments.

Change-Id: Iaba6c1be53e994c95f7f5c350ee018adcd337a6e
diff --git a/tempest/lib/services/network/metering_labels_client.py b/tempest/lib/services/network/metering_labels_client.py
old mode 100644
new mode 100755
index 2350ecd..12a5834
--- a/tempest/lib/services/network/metering_labels_client.py
+++ b/tempest/lib/services/network/metering_labels_client.py
@@ -16,18 +16,41 @@
 class MeteringLabelsClient(base.BaseNetworkClient):
 
     def create_metering_label(self, **kwargs):
+        """Creates an L3 metering label.
+
+        Available params: see http://developer.openstack.org/
+                              api-ref-networking-v2-ext.html#
+                              createMeteringLabel
+        """
         uri = '/metering/metering-labels'
         post_data = {'metering_label': kwargs}
         return self.create_resource(uri, post_data)
 
     def show_metering_label(self, metering_label_id, **fields):
+        """Shows details for a metering label.
+
+        Available params: see http://developer.openstack.org/
+                              api-ref-networking-v2-ext.html#showMeteringLabel
+        """
         uri = '/metering/metering-labels/%s' % metering_label_id
         return self.show_resource(uri, **fields)
 
     def delete_metering_label(self, metering_label_id):
+        """Deletes an L3 metering label.
+
+        Available params: see http://developer.openstack.org/
+                              api-ref-networking-v2-ext.html#
+                              deleteMeteringLabel
+        """
         uri = '/metering/metering-labels/%s' % metering_label_id
         return self.delete_resource(uri)
 
     def list_metering_labels(self, **filters):
+        """Lists all L3 metering labels that belong to the tenant.
+
+        Available params: see http://developer.openstack.org/
+                              api-ref-networking-v2-ext.html#
+                              listMeteringLabels
+        """
         uri = '/metering/metering-labels'
         return self.list_resources(uri, **filters)