Fix EC2 credentials create to use admin user credentials.

Keystone has changed to no longer authenticate with the bootstrap
token for EC2 creds.The identity LWRP has been change to bootstrap
the admin user and then use admin creds (not the bootstrap token)
to create EC2 creds.

Closes-Bug: #1274870

Change-Id: I96b9f18b84194e2128a867cb6b89ba8b24c59d6e
Merge "Fix EC2 credentials create to use admin user credentials."