Hi.
I think it would be a good idea to exit multichaind and throw an error if you provide parameters for certificate and private key but multichaind cannot find / open the files.
For now, MultiChain starts up as normal and you will only realize the problem when explicitely looking into debug.log for a line like:
2018-09-20 07:31:43 ThreadRPCServer ERROR: missing server certificate file /home/mc/cert.pem
2018-09-20 07:31:43 ThreadRPCServer ERROR: missing server private key file /home/mc/key.pem
Greetings,
Alex