innodb_redo_log_encrypt does not behave correctly with SET PERSIST_ONLY

While testing PR-4556, below Scenario was executed:

Start the server with innodb_redo_log_encrypt=keyring_key
set persist_only innodb_redo_log_encrypt=master_key;
shutdown;
try to restart the server
In ideal scenario, the server should not come up because the redo logs are encrypted with keyring_key
But, currently the server starts and if we select the value of innodb_redo_log_encrypt, it is shown as OFF