MaxCtrl cluster sync doesn't work with encrypted passwords

Overview

When encrypted passwords are used with the MaxCtrl cluster sync command, the passwords are sent encrypted with the key on the source MaxScale. If the destination MaxScales have different encryption keys, the password decrypts into garbage.

Step to Reproduce

• Use encrypted passwords on two MaxScale instances with different encryption keys
• Alter the password of a service, monitor or server on one MaxScale
• Execute maxctrl cluster sync
• Restart second MaxScale →results in an error