Fix the endpoint url trailing slash issue

Keystone catalog url could be with or without the trailing slash.
Removing it when get the endpoint.

Change-Id: I55bbfb5823957ff50d9a588c9cc1a9faebecffff
diff --git a/telemetry_tempest_plugin/scenario/test_telemetry_integration.py b/telemetry_tempest_plugin/scenario/test_telemetry_integration.py
index eb76023..654414d 100644
--- a/telemetry_tempest_plugin/scenario/test_telemetry_integration.py
+++ b/telemetry_tempest_plugin/scenario/test_telemetry_integration.py
@@ -61,7 +61,7 @@
                 raise Exception("%s interface not found for endpoint %s" %
                                 (endpoint_type,
                                  opt_section.catalog_type))
-            return endpoints[0]
+            return endpoints[0].rstrip('/')
 
         else:
             if not endpoint_type.endswith("URL"):
@@ -72,7 +72,7 @@
             if not endpoints:
                 raise Exception("%s endpoint not found" %
                                 opt_section.catalog_type)
-            return endpoints[0]['endpoints'][0][endpoint_type]
+            return endpoints[0]['endpoints'][0][endpoint_type].rstrip('/')
 
     def _prep_test(self, filename):
         admin_auth = self.os_admin.auth_provider.get_auth()