title: Swagger codegen overrides query parameter with a header parameter that has the same name
body: <p>I have a swagger definition that has a query and a header that share the same name:</p>
  <pre><code>parameters:
    qry_param:
      name: appid
      in: query
      required: true
      type: string
    hdr_param:
      name: appid
      in: header
      required: false
      type: string
  ...
  paths:
    '/some/path/here':
      post:
        parameters:
          - $ref: '#/parameters/hdr_param'
          - $ref: '#/parameters/qry_param'
  </code></pre>
  <p>When I try to generate a client with <code>swagger-codegen-maven-plugin</code> only request header is generated for this parameter.</p>
  <p>What can I do to generate both?</p>