rhbz990825 - Admin user list was not being fetched from configuration.

This was caused inadvertently when introducing JNDI configuration.
rhbz990825 - Refactor code that fetches admin users.

Using guava "niceness" now.
rhbz990825 - Change imports on ApplicationConfiguration.
Merge pull request #108 from zanata/rhbz990825

rhbz990825 - Admin user list was not being fetched from configuration.