Enhancement: Bump Reva

This updates the ownCloud Reva dependency to commit `a122a9538794530267743edfd5dc67b48aa90325`.
Changelog: https://github.com/owncloud/reva/compare/751223b32d4852c73a43388f6f55308c2065afeb...a122a9538794530267743edfd5dc67b48aa90325

https://github.com/owncloud/ocis/pull/11808
