Merge pull request android-async-http#54 from MasterXval/master

Corrected NullPointerException on request with 204 http status

Author: loopj

src/com/loopj/android/http/AsyncHttpClient.java

@@ -146,6 +146,9 @@ public void process(HttpRequest request, HttpContext context) {
         httpClient.addResponseInterceptor(new HttpResponseInterceptor() {
             public void process(HttpResponse response, HttpContext context) {
                 final HttpEntity entity = response.getEntity();
+                if (entity == null) {
+                    return;
+                }
                 final Header encoding = entity.getContentEncoding();
                 if (encoding != null) {
                     for (HeaderElement element : encoding.getElements()) {

src/com/loopj/android/http/AsyncHttpResponseHandler.java

@@ -211,8 +211,8 @@ void sendResponseMessage(HttpResponse response) {
             HttpEntity temp = response.getEntity();
             if(temp != null) {
                 entity = new BufferedHttpEntity(temp);
+                responseBody = EntityUtils.toString(entity);
             }
-            responseBody = EntityUtils.toString(entity);
         } catch(IOException e) {
             sendFailureMessage(e, null);
         }