Fetch fingerprint before credentials

Some implementations choose to close the certificate command after
granting user/password. Make sure we get the certificate first.

misc/prepfish.py

@@ -285,6 +285,7 @@ def store_redfish_cert(bmc):
             certout.write(peercert)
 
 def main():
+    get_redfish_fingerprint()
     bmcuser, bmcpass = get_redfish_creds()
     bmc = enable_host_interface()
     store_redfish_cert(bmc)