Config options: move set default opt of db section to centralized place

Currently markus_z have centralized database section in
nova/conf/database.py. But in nova/config.py, there is a
part of database section that set the default options of
oslo_db. The set_default_opt include register_opt and should be
moved to centralized place.

Change-Id: Ic94991b009dfaa076a5f285b43018e473e9e074f
Implements: blueprint centralize-config-options-newton

nova/cmd/manage.py

@@ -89,7 +89,6 @@ from nova import utils
 from nova import version
 
 CONF = nova.conf.CONF
-CONF.import_opt('connection', 'oslo_db.options', group='database')
 
 QUOTAS = quota.QUOTAS
 

nova/conf/database.py

@@ -13,10 +13,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from nova.conf import paths
 
 from oslo_config import cfg
 from oslo_db import options as oslo_db_options
 
+_DEFAULT_SQL_CONNECTION = 'sqlite:///' + paths.state_path_def('nova.sqlite')
+
 
 # NOTE(sdague): we know of at least 1 instance of out of tree usage
 # for this config in RAX. They used this because of performance issues
@@ -87,7 +90,8 @@ api_db_opts = [
 
 
 def register_opts(conf):
-    conf.register_opts(oslo_db_options.database_opts, 'database')
+    oslo_db_options.set_defaults(conf, connection=_DEFAULT_SQL_CONNECTION,
+                         sqlite_db='nova.sqlite')
     conf.register_opt(db_driver_opt)
     conf.register_opts(api_db_opts, group='api_database')
 

nova/config.py

@@ -15,12 +15,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from oslo_db import options
 from oslo_log import log
 
 from nova.common import config
 import nova.conf
-from nova.conf import paths
 from nova.db.sqlalchemy import api as sqlalchemy_api
 from nova import rpc
 from nova import version
@@ -28,8 +26,6 @@ from nova import version
 
 CONF = nova.conf.CONF
 
-_DEFAULT_SQL_CONNECTION = 'sqlite:///' + paths.state_path_def('nova.sqlite')
-
 _EXTRA_DEFAULT_LOG_LEVELS = ['glanceclient=WARN']
 
 
@@ -40,8 +36,6 @@ def parse_args(argv, default_config_files=None, configure_db=True,
     # and add only the extra levels that Nova needs
     log.set_defaults(default_log_levels=log.get_default_log_levels() +
                      _EXTRA_DEFAULT_LOG_LEVELS)
-    options.set_defaults(CONF, connection=_DEFAULT_SQL_CONNECTION,
-                         sqlite_db='nova.sqlite')
     rpc.set_defaults(control_exchange='nova')
     config.set_middleware_defaults()