Test non-default online.swagger.io Agent error
Test non-default online.swagger.io Agent error

Ensure the test still works if https://online.swagger.io is not the
default proto/host.

Signed-off-by: Kevin Locke <ffb4761cba839470133bee36aeb139f58d7dbaa9@kevinlocke.name>

kevinoid/swagger-spec-validator,kevinoid/swagger-spec-validator,kevinoid/swagger-spec-validator