wsrep recovery from mysqld_safe may run with silent log verbosity

[temeo]

Seen for example here: #381. This will cause the recovery log to miss the wsrep position output.

Error log verbosity should be the default, log_error_verbosity for recovery should be set in these options https://github.com/codership/mysql-wsrep/blob/5.7/scripts/mysqld_safe.sh#L252