remove unnecessary db config for nova-metadata-api

[cbjchen,r=]
nova-metadata-api only access db through nova-conductor.
And the db config was left wrong when db relation is
not ready.

hooks/neutron_utils.py

@@ -299,9 +299,7 @@ NOVA_CONF = "/etc/nova/nova.conf"
 
 NOVA_CONFIG_FILES = {
     NOVA_CONF: {
-        'hook_contexts': [context.SharedDBContext(ssl_dir=NOVA_CONF_DIR),
-                          context.PostgresqlDBContext(),
-                          NetworkServiceContext(),
+        'hook_contexts': [NetworkServiceContext(),
                           NeutronGatewayContext(),
                           SyslogContext(),
                           context.ZeroMQContext(),

templates/havana/nova.conf

@@ -12,7 +12,6 @@ use_syslog = {{ use_syslog }}
 api_paste_config=/etc/nova/api-paste.ini
 enabled_apis=metadata
 multi_host=True
-{% include "parts/database" %}
 neutron_metadata_proxy_shared_secret={{ shared_secret }}
 service_neutron_metadata_proxy=True
 # Access to message bus

tests/basic_deployment.py

@@ -551,7 +551,6 @@ class QuantumGatewayBasicDeployment(OpenStackAmuletDeployment):
             'api_paste_config': '/etc/nova/api-paste.ini',
             'enabled_apis': 'metadata',
             'multi_host': 'True',
-            'sql_connection': db_uri,
             'service_neutron_metadata_proxy': 'True',
             'rabbit_userid': 'neutron',
             'rabbit_virtual_host': 'openstack',