OIDC Discovery Provider server logHandler errors for Incoming request logs

[hipper]

When debug logs are enabled, the OIDC Discovery Provider server logHandler errors, when attempting to log "Incoming request"

Steps to reproduce:

1. Update configuration to enable Debug level logging
2. Start OIDC Discovery Provider server
3. Send a request and observe logged error

Example error logged:

{"level":"debug","logrus_error":"can not add field \"user-agent\"","method":"GET"...}