Ephemeral db doesn't support diff causing error in install_config

[rsmekala]

Description of Issue/Question

Netconf traces:

<get-configuration compare="rollback" rollback="0" format="text"/>]]>]]>
Aug 12 15:19:37 [NETCONF] - [22322] Outgoing: <rpc-reply>
Aug 12 15:19:37 [NETCONF] - [22322] Outgoing: <rpc-error>
Aug 12 15:19:37 [NETCONF] - [22322] Outgoing: <error-type>protocol</error-type>