Describe the bug
When setting a BaseUrl with a port, and the description file doesn't contain any servers, the port is omitted from the default server.

To Reproduce
Steps to reproduce the current behavior:
Create OpenApiReaderSettings with BaseUrl set to http://demo.testfire.net:8080
Create any OpenApiReader instance with these settings
Attempt to deserialize this properties file: http://demo.testfire.net:8080/swagger/properties.json

The resulting OpenApiDocument.Servers will contain the server "http://demo.testfire.net" (without the port number).

Expected behavior
The resulting OpenApiDocument.Servers should contain the server "http://demo.testfire.net:8080"