dev-db/postgresql: Add 9.5 Beta 2

dev-db/postgresql: Add 9.5 Beta 2

Many bugs and issues reported by our users and contributors have been
fixed since the release of Beta1. These include:

* Many documentation fixes and improvements
* Rename PQsslAttributes() to PQsslAttributeNames()
* Pass extra data to pgworkers for context
* Fix other issues with parallel workers
* Fix multiple issues with BRIN indexes
* Fix problems with commit timestamps and replication
* Put back ssl_renegotiation_limit, set to 0

Package-Manager: portage-2.2.20.1