Change the default EC key to secp384r1

prime256v1 is okay for now, but secp384r1 is more future-proof (gives us
a couple more years) and in this case does not really have any
drawbacks.

Tested: Checked to see that a new secp384r1 key is generated on first
        boot and the generate CSR redfish option works.

Change-Id: I334fc56db3dd55058a4c6780f8966bcc48d8f816
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>