Make killing a locker an ERROR event.

[nathanhruby]

At least in apache, killing a locker with SIGKILL from inside opcache prevents the child process from emitting a corresponding log event to the access or error logs, therefore requests are termed with no record. This makes is incredibly difficult to debug problems espically on systems with high counts of cache restarts. Since INFO level is far too noisy for production use, switch the killing to a higher level so we can see it easier.

[laruence]

merged, also committed to php-src https://github.com/php/php-src/commit/837eeefee9e01156b364a4b0e9cff8d9f0a1a1d5 thanks

[nathanhruby]

Awesome, thank you!