Cleanup orphaned code in sqlalchemy API

There were several methods in the sqlalchemy code that were no longer
being used anywhere. While some of these have potential for being useful,
they are not in use and should not be sitting around the codebase waiting
for someone to need them.

Change-Id: Ic30d27b29d19de5470c9fffadc136988899525ca

cinder/db/sqlalchemy/api.py

@@ -396,19 +396,6 @@ def service_get_by_host_and_topic(context, host, topic):
     return result
 
 
-@require_admin_context
-def _service_get_all_topic_subquery(context, session, topic, subq, label):
-    sort_value = getattr(subq.c, label)
-    return model_query(context, models.Service,
-                       func.coalesce(sort_value, 0),
-                       session=session, read_deleted="no").\
-        filter_by(topic=topic).\
-        filter_by(disabled=False).\
-        outerjoin((subq, models.Service.host == subq.c.host)).\
-        order_by(sort_value).\
-        all()
-
-
 @require_admin_context
 def service_get_by_args(context, host, binary):
     results = model_query(context, models.Service).\
@@ -1277,16 +1264,6 @@ def volume_destroy(context, volume_id):
                     'updated_at': literal_column('updated_at')})
 
 
-@require_admin_context
-def volume_detach(context, attachment_id):
-    session = get_session()
-    with session.begin():
-        volume_attachment_ref = volume_attachment_get(context, attachment_id,
-                                                      session=session)
-        volume_attachment_ref['attach_status'] = 'detaching'
-        volume_attachment_ref.save(session=session)
-
-
 @require_admin_context
 def volume_detached(context, volume_id, attachment_id):
     """This updates a volume attachment and marks it as detached.
@@ -1968,12 +1945,6 @@ def _volume_image_metadata_update(context, volume_id, metadata, delete,
                                      session=session)
 
 
-@require_context
-@require_volume_exists
-def volume_metadata_get_item(context, volume_id, key):
-    return _volume_user_metadata_get_item(context, volume_id, key)
-
-
 @require_context
 @require_volume_exists
 def volume_metadata_get(context, volume_id):
@@ -3785,11 +3756,6 @@ def _consistencygroup_data_get_for_project(context, project_id,
     return (0, result[0] or 0)
 
 
-@require_admin_context
-def consistencygroup_data_get_for_project(context, project_id):
-    return _consistencygroup_data_get_for_project(context, project_id)
-
-
 @require_context
 def _consistencygroup_get(context, consistencygroup_id, session=None):
     result = model_query(context, models.ConsistencyGroup, session=session,