Check your grants for keystone databse.. GRANT ALL ON keystone.* TO '[YOURKEYSTONE_USER]'@'%' IDENTIFIED BY '[YOUR_KEYSTONEDB_PASSWORD]'; FLUSH PRIVILEGES;

There is an error in your keystone setup .Due to

[root@dfw02 ~(keystone_admin)]$ mysql -u root -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 168
Server version: 5.5.36-MariaDB MariaDB Server
Copyright (c) 2000, 2014, Oracle, Monty Program Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> SELECT User, Host, Password FROM mysql.user WHERE User LIKE 'keystone%' ;
+----------+-----------+-------------------------------------------+
| User     | Host      | Password                                  |
+----------+-----------+-------------------------------------------+
| keystone | localhost | *936E8F7AB2E21B47F6C9A7E5D9FE14DBA2255E5A |
| keystone | %         | *936E8F7AB2E21B47F6C9A7E5D9FE14DBA2255E5A |
+----------+-----------+-------------------------------------------+
2 rows in set (0.00 sec)

Running system doesn't have 'keystone_admin' user.

Same query been run against your database either won't contain entry for 'keystone_admin' or entry been found would have password different from placed in keystone.conf file Thus your keystone.conf contains wrong mysql connection string :-

[sql]
    connection = mysql://keystone_admin:#######@10.10.155.11/keystone

I would expect you to perform keystone setup from scratch properly.
Personally, I cannot remind user keystone_admin to be created, just keystone
Keystone Setup from scratch here

i had a similar issue when I was trying to run packstack. the install would fail with the keystone-manage db_sync error. I had HOSTNAME.DOMAIN configured as my hostname. Upon cheking the keystone database, saw that the host was appearing as localhost. I removed the domain name from the /etc/sysconfig/network and only left the hostname there. Next attempt at packstack worked like a charm...

Having said that, I am now going to try playing weith the keystone db in mysql and change the hostname to my actual HOSTNAME.DOMAINNAME and run packstack.. I will let you guys know how I go.

-d