BUG #13642: no backup_label file in PG_DATA after pg_stop_backup();

The following bug has been logged on the website:

Bug reference: 13642
Logged by: Amir Rohan
Email address: amir(dot)rohan(at)mail(dot)com
PostgreSQL version: 9.4.4
Operating system: Linux
Description:

SELECT pg_start_backup('backup1');
SELECT pg_stop('backup1');

Doesn't create the `backup_label` described in the docs (I'm assuming
"cluster directory" means data directory, e.g. $PGDATA):
http://www.postgresql.org/docs/current/static/continuous-archiving.html

They further state:
"The file is critical to the integrity of the backup, should you need to
restore from it."

Are my backups safe or not?