Keep parts on 307, close AsyncHttpClient#1643

Author: slandelle

client/src/main/java/org/asynchttpclient/netty/handler/intercept/Redirect30xInterceptor.java

@@ -111,6 +111,9 @@ else if (request.getByteBufferData() != null)
             requestBuilder.setBody(request.getByteBufferData());
           else if (request.getBodyGenerator() != null)
             requestBuilder.setBody(request.getBodyGenerator());
+          else if (isNonEmpty(request.getBodyParts())) {
+            requestBuilder.setBodyParts(request.getBodyParts());
+          }
         }
 
         requestBuilder.setHeaders(propagatedHeaders(request, realm, keepBody));