BUG #14000: initdb installs in 9.4 by default

The following bug has been logged on the website:

Bug reference: 14000
Logged by: Evgeniy Shishkin
Email address: itparanoia(at)gmail(dot)com
PostgreSQL version: 9.5.1
Operating system: centos 7
Description:

Running initdb without datadir parameter initializes in 9.4/data

/usr/pgsql-9.5/bin/initdb --locale=en_US.UTF-8 --encoding=UNICODE
The files belonging to this database system will be owned by user
"postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

creating directory /var/lib/pgsql/9.4/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
creating template1 database in /var/lib/pgsql/9.4/data/base/1 ... ok
initializing pg_authid ... ok
initializing dependencies ... ok
creating system views ... ok
loading system objects' descriptions ... ok
creating collations ... ok
creating conversions ... ok
creating dictionaries ... ok
setting privileges on built-in objects ... ok
creating information schema ... ok
loading PL/pgSQL server-side language ... ok
vacuuming database template1 ... ok
copying template1 to template0 ... ok
copying template1 to postgres ... ok
syncing data to disk ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:

/usr/pgsql-9.5/bin/pg_ctl -D /var/lib/pgsql/9.4/data -l logfile start