I had the same kind of errors after an update from 9.1.2 to 9.1.3 on CentOS 7.
The FAQ "File is locked - how to unlock" was not helpful. Redis was already enabled as a locking mechanism.
I finally found this thread and following Galumbo idea: I switched form PHP 5.4.6 to PHP 7.0 and the problem was solved (SSL was already enabled).