Change: Update reva config

* EOS homes are not configured with an enable-flag anymore, but with a dedicated storage driver.
* We're using it now and adapted default configs of storages

https://github.com/owncloud/ocis/pull/336
https://github.com/owncloud/ocis/pull/337
https://github.com/owncloud/ocis/pull/338
https://github.com/owncloud/ocis-reva/pull/891
