Use section in first element in user_ldap

Before:
![screen shot 2014-09-10 at 18 48 34](https://cloud.githubusercontent.com/assets/878997/4221487/6f42afc0-390a-11e4-87af-1073b93a2e89.png)

After:
![screen shot 2014-09-10 at 18 48 59](https://cloud.githubusercontent.com/assets/878997/4221486/6f3aa366-390a-11e4-9259-5caf7c4a8962.png)

@blizzz @jancborchardt

\cc @karlitschek since this is against stable7 - should be cherry-picked to master