`openstack undercloud install` results in the following failure while trying to insert data into keystone. 

The following cert files already exist, use --rebuild to remove the existing files before regenerating:
/mnt/state/etc/keystone/ssl/certs/ca.pem already exists
/mnt/state/etc/keystone/ssl/private/signing_key.pem already exists
/mnt/state/etc/keystone/ssl/certs/signing_cert.pem already exists
Connection to 172.16.172.3 closed.
PKI initialization in init-keystone is deprecated and will be removed.
+ ENDPOINT_LIST='--glance-password 11065b807c93ae8898f6aa18f4d05ae891633c08
    --heat-password 318f47c5b7064871ccf65f46cdfac9a6cabbf1cd
    --neutron-password 48477a951cab09fe3d608281848c49581c671cef
    --nova-password 78e52268a3427c6b66e661113c520d1eba3fe4fa
    --tuskar-password c92b552d1c7023b1534df880a081ef6aca3ccd73
    --ironic-password f1939744ca2c798b3055bbaa6cb760e4d5c4eb3e
    --ceilometer-password 061c0f1fe0ef0a66498dd9e2939c7fdbd1aae35a'
+ REGISTER_SERVICE_OPTS=
+ keystone role-create --name=ResellerAdmin
/usr/lib/python2.7/site-packages/keystoneclient/shell.py:65: DeprecationWarning: The keystone CLI is deprecated in favor of python-openstackclient. For a Python library, continue using python-keystoneclient.
  'python-keystoneclient.', DeprecationWarning)
Authorization Failed: An unexpected error prevented the server from fulfilling your request. (HTTP 500) (Request-ID: req-6c7f29be-c8cd-429f-8950-828b77d01d31)
[2015-06-01 11:56:59,530] (os-refresh-config) [ERROR] during post-configure phase. [Command '['dib-run-parts', '/usr/libexec/os-refresh-config/post-configure.d']' returned non-zero exit status 1]

[2015-06-01 11:56:59,531] (os-refresh-config) [ERROR] Aborting...
ERROR: openstack Command 'instack-install-undercloud' returned non-zero exit status

in the keystone log I see:

2015-06-01 11:56:57.081 8158 WARNING oslo_config.cfg [-] Option "connection" from group "sql" is deprecated. Use option "connection" from group "database".
2015-06-01 11:56:57.199 8158 WARNING keystone.common.controller [-] RBAC: Bypassing authorization
2015-06-01 11:56:57.306 8169 WARNING oslo_config.cfg [-] Option "connection" from group "sql" is deprecated. Use option "connection" from group "database".
2015-06-01 11:56:57.493 8174 WARNING oslo_config.cfg [-] Option "connection" from group "sql" is deprecated. Use option "connection" from group "database".
2015-06-01 11:56:58.648 9299 WARNING keystone.cli [-] keystone-manage pki_setup is not recommended for production use.
2015-06-01 11:56:59.229 8192 WARNING oslo_config.cfg [-] Option "connection" from group "sql" is deprecated. Use option "connection" from group "database".
2015-06-01 11:56:59.502 8192 ERROR keystone.common.wsgi [-] No module named backends.sql
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi Traceback (most recent call last):
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/common/wsgi.py", line 239, in __call__
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     result = method(context, **params)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/token/controllers.py", line 145, in authenticate
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     auth_token_data, roles_ref=roles_ref, catalog_ref=catalog_ref)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/token/provider.py", line 333, in issue_v2_token
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     self._create_token(token_id, data)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/token/provider.py", line 190, in _create_token
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     self._persistence.get_token(token_id)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/token/provider.py", line 164, in _persistence
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     self._persistence_manager = persistence.PersistenceManager()
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/common/dependency.py", line 193, in wrapper
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     self.__wrapped_init__(*args, **kwargs)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/token/persistence/core.py", line 50, in __init__
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     super(PersistenceManager, self).__init__(CONF.token.driver)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/keystone/common/manager.py", line 70, in __init__
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     self.driver = importutils.import_object(driver_name)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/oslo_utils/importutils.py", line 38, in import_object
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     return import_class(import_str)(*args, **kwargs)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi   File "/usr/lib/python2.7/site-packages/oslo_utils/importutils.py", line 27, in import_class
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi     __import__(mod_str)
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi ImportError: No module named backends.sql
2015-06-01 11:56:59.502 8192 TRACE keystone.common.wsgi

Keystone is running andI see the backends.sql code so I beleive there is an error in the keystone.conf file where it is pointing to the backends stuff.