More work on AHC 78 thanks to Dominic Tootell

Author: jfarcand

src/main/java/com/ning/http/multipart/MultipartBody.java

@@ -377,7 +377,7 @@ private FilePart generateClientFilePart(com.ning.http.client.Part part)
     private StringPart generateClientStringpart(com.ning.http.client.Part part) {
         com.ning.http.client.StringPart stringPart = (com.ning.http.client.StringPart) part;
 
-        StringPart currentPart = new StringPart(stringPart.getName(), stringPart.getValue());
+        StringPart currentPart = new StringPart(stringPart.getName(), stringPart.getValue(), stringPart.getCharset());
         return currentPart;
     }