Replace AuthMode.OFF by AuthMode.NONE

[cbornet]

When using application.yml to configure nakadi.oauth2.mode YAML parser translates OFF to false if you don't put quotes and the Spring property binding fails with

Caused by: java.lang.IllegalStateException: Cannot convert value of type 'java.lang.String' to required type 'org.zalando.nakadi.config.SecuritySettings$AuthMode': no matching editors or conversion strategy found
	at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:307)
	at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:109)
	at org.springframework.beans.TypeConverterSupport.doConvert(TypeConverterSupport.java:64)
	... 98 more

The workaround is to add quotes like nakadi.oauth2.mode: "OFF" but it is a bit awkward and you can miss it when running your service.

Adding a NONE value in the enum that has the same effect as OFF would prevent that and you could keep OFF for backward compatibility.

[lmontrieux]

Thank you @cbornet for your suggestion. This looks like a nice improvement, and could be a good first issue for someone looking into contributing to Nakadi.

[adyach]

The workaround is to add quotes like nakadi.oauth2.mode: "OFF" but it is a bit awkward and you can miss it when running your service.

@lmontrieux @cbornet could you please elaborate on that? for me it is not clear what the issue is
to have quotes.