Fix doc build errors with SQLAlchemy 0.9

The docs failed to build when using SQLAlchemy 0.9. The following
errors occur:

 sphinx.errors.SphinxWarning:
 /opt/stack/keystone/keystone/common/sql/__init__.py:docstring of
 keystone.common.sql.relationship:53: ERROR: Unknown interpreted text
 role "paramref".

To fix this, relationship was removed from keystone.common.sql. It
was a reference to the same in sqlalchemy.orm, so the user was
changed to use sqlalchemy.orm.relationship.

 sphinx.errors.SphinxWarning:
 /opt/stack/keystone/keystone/openstack/common/db/sqlalchemy/utils.py:
 docstring of keystone.openstack.common.db.sqlalchemy.utils.or_:26:
 WARNING: more than one target found for cross-reference u'and_':
 keystone.common.sql.core.and_, keystone.common.sql.and_

To fix this, and_ was removed from keystone.common.sql. It was a
reference to the same in sqlalchemy, so the users were changed to use
sqlalchemy.and_.

Closes-Bug: #1296333
Change-Id: I39a91a5a30d351c4538d437c7584544bdb59c65e

keystone/assignment/backends/sql.py

@@ -13,6 +13,7 @@
 # under the License.
 
 import six
+import sqlalchemy
 
 from keystone import assignment
 from keystone import clean
@@ -291,7 +292,7 @@ class Assignment(assignment.Driver):
         else:
             raise AttributeError(_("Must specify either domain or project"))
 
-        sql_constraints = sql.and_(
+        sql_constraints = sqlalchemy.and_(
             RoleAssignment.type == assignment_type,
             RoleAssignment.target_id == target_id,
             Role.id == RoleAssignment.role_id,
@@ -309,7 +310,7 @@ class Assignment(assignment.Driver):
         else:
             assignment_type = AssignmentType.GROUP_PROJECT
 
-        group_sql_conditions = sql.and_(
+        group_sql_conditions = sqlalchemy.and_(
             RoleAssignment.type == assignment_type,
             entity.id == RoleAssignment.target_id,
             RoleAssignment.actor_id.in_(group_ids))

keystone/catalog/backends/sql.py

@@ -14,6 +14,7 @@
 # under the License.
 
 import six
+import sqlalchemy
 
 from keystone import catalog
 from keystone.catalog import core
@@ -58,7 +59,7 @@ class Service(sql.ModelBase, sql.DictBase):
     id = sql.Column(sql.String(64), primary_key=True)
     type = sql.Column(sql.String(255))
     extra = sql.Column(sql.JsonBlob())
-    endpoints = sql.relationship("Endpoint", backref="service")
+    endpoints = sqlalchemy.orm.relationship("Endpoint", backref="service")
 
 
 class Endpoint(sql.ModelBase, sql.DictBase):

keystone/common/sql/core.py

@@ -59,11 +59,9 @@ Boolean = sql.Boolean
 Text = sql.Text
 UniqueConstraint = sql.UniqueConstraint
 PrimaryKeyConstraint = sql.PrimaryKeyConstraint
-relationship = sql.orm.relationship
 joinedload = sql.orm.joinedload
 # Suppress flake8's unused import warning for flag_modified:
 flag_modified = flag_modified
-and_ = sql.and_
 
 
 def initialize():