[Regression] Cannot start the web server when custom_content_path is set

[madduci]

I have updated my existing server to the tag v8.6.0-1 of this repository.

Unfortunately, when the property for a custom folder is set, such as:

hapi:
   fhir:
     custom_content_path: ./custom

The integration tests (and the server) don't work anymore, with the error:

Error creating bean with name 'resourceHandlerMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: 
Failed to instantiate [org.springframework.web.servlet.HandlerMapping]: 
Factory method 'resourceHandlerMapping' threw exception with message: 
Resource location does not end with slash: file:./custom

As an example, the test MdmTest.testApplicationStartedSuccessfully cannot be started. Providing the suggested trailing slash, e.g. ./custom/, doesn't work either, giving the same error.

With the tag v8.4.0-3 of this repository, it was working.