remove Location: header checks for absolute URL

https://tools.ietf.org/html/rfc7231#section-7.1.2

   The "Location" header field is used in some responses to refer to a
   specific resource in relation to the response.  The type of
   relationship is defined by the combination of request method and
   status code semantics.

     Location = URI-reference

   The field value consists of a single URI-reference.  When it has the
   form of a relative reference ([RFC3986], Section 4.2), the final
   value is computed by resolving it against the effective request URI
   ([RFC3986], Section 5).


There is even an example with no scheme:

     Location: /People.html#tim



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1770786 13f79535-47bb-0310-9956-ffa450edef68