Bump gnocchi version to 4.6.1

Gnnochi has made a new patch release, let's use it.

Change-Id: I6a56639d9b61944cf2ea5efd1063ebd3c8950113

Author: osfrickler

kolla/common/sources.py

@@ -65,7 +65,7 @@
                      'glance-${openstack_branch}.tar.gz')},
     'gnocchi-base': {
         'type': 'git',
-        'reference': '4.6.0',
+        'reference': '4.6.1',
         'location': ('https://github.com/gnocchixyz/'
                      'gnocchi.git')},
     'heat-base': {