[CXF-4920] TransformationInInterceptor fails when XML contains same namespace with different prefixes

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1461456 13f79535-47bb-0310-9956-ffa450edef68
[CXF-4927] HttpHeaders.getRequestHeader needs to return null for missing headers

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1461457 13f79535-47bb-0310-9956-ffa450edef68