Fix service_name in process_certificates call

Fix service_name when calling process_certificates so it matches
what ApacheSSLContext expects.

Ceilometers Apache config is rendered using
ceilometer_contexts.ApacheSSLContext. This class is a subclass of
charmhelpers.contrib.openstack.context.ApacheSSLContext. The
ceilometer specialised class sets 'service_namespace = "ceilometer"'.
This is then used by parent class to set the destination for certs
and keys to:

ssl_dir = os.path.join('/etc/apache2/ssl/', self.service_namespace)

The code to process incoming certificates from the certificates
relation does something very similar.
charmhelpers.contrib.openstack.cert_utils.process_certificates
takes a service_name parameter. It uses this to set the destination
directory that incoming certificates will be stored in:

ssl_dir = os.path.join('/etc/apache2/ssl/', service_name)

Obviously these two ssl directories need to match. But they do not
because process_certificates is currently called like this:

cert_utils.process_certificates('ceilometer-api', relation_id, unit)

Change-Id: I41a26d00b4d2b22a5cfd2ef38ec76f2efd13f75b
Closes-Bug: #1849292

hooks/ceilometer_hooks.py

@@ -492,7 +492,7 @@ def certs_joined(relation_id=None):
 def certs_changed(relation_id=None, unit=None):
     @restart_on_change(restart_map())
     def _certs_changed():
-        cert_utils.process_certificates('ceilometer-api', relation_id, unit)
+        cert_utils.process_certificates('ceilometer', relation_id, unit)
         configure_https()
     _certs_changed()
 

unit_tests/test_ceilometer_hooks.py

@@ -477,5 +477,5 @@ class CeilometerHooksTest(CharmTestCase):
     def test_certs_changed(self, _process_certificates, _configure_https):
         hooks.hooks.execute(['hooks/certificates-relation-changed'])
         _process_certificates.assert_called_once_with(
-            'ceilometer-api', None, None)
+            'ceilometer', None, None)
         _configure_https.assert_called_once_with()