mysql.server script not correctly handle --pid-file.

If I start mysql with --pid-file argument:

service mysql start --pid-file=/var/lib/mysql/1234.pid

I can not stop it with
service mysql stop --pid-file=/var/lib/mysql/1234.pid

I got this error:
MySQL server PID file could not be found!

This is because parse_server_arguments function in script does not parse --pid-file, the variable $mysqld_pid_file_path will always be empty.

Thanks.