FilePart file not properly closed on UnknownHostException
Running Java command line application on machine with the following specs:

Windows 7 Professional - 64 bit
Service Pack 1
32 GB RAM
Java Version 1.8.0_91
Java SE Runtime Environment (build 1.8.0_91-b15)
Java HotSpot 64-bit Server VM (build 25.91-b15, mixed mode)

If synchronous execute() method called and UnknownHostException thrown, FilePart file is not closed and a subsequent ATOMIC_MOVE call fails with error: 'The process cannot access the file because it is being used by another process.'

```
    // code snippet with sensitive portions removed
    void transmit(final File file) {
        try {
            String authorization = "";

           ** stuff here to get authorization code

            BoundRequestBuilder request = client.preparePost(String.format("%s/api/files/save", url))
                    .addHeader("Authorization", authorization)
                    .addHeader("Content-Type", "multipart/form-data")
                    .addBodyPart(new StringPart("transferId", UUID.randomUUID().toString()))
                    .addBodyPart(new StringPart("timestamp", Timestamp.from(Instant.now()).toString()))
                    .addBodyPart(new FilePart("file", file, "text/plain"));

            Response response = request.execute().get();
            if ( response != null ) {
                 // do stuff with response here
            }
        } catch ( Exception ex ) {
           // code to copy file to a different folder fails here
           // Reason: The process cannot access the file because it is being used by another process.
           // using the following code to move the file
           Files.move(<source path>, <dest path>, ATOMIC_MOVE);
        }
    }

```