Keylime: keylime registrar dos due to incompatible database entry handling

A flaw was found in Keylime, a remote attestation solution, where strict type checking introduced in version 7.12.0 prevents the registrar from reading database entries created by previous versions, for example, 7.11.0. Specifically, older versions store agent registration data as bytes, whereas the updated registrar expects str. This issue leads to an exception when processing agent registration requests, causing the agent to fail.