Merge pull request #12 from messagebird/wrong-content-type

Set the Content-Type header to text/plain for GET, DELETE requests

Author: marcelcorso

api/src/main/java/com/messagebird/MessageBirdServiceImpl.java

@@ -186,11 +186,11 @@ public <P> HttpURLConnection getConnection(final String serviceUrl, final P post
             // could have just used rquestType as it is
             connection.setDoOutput(false);
             connection.setRequestMethod("DELETE");
-            connection.setRequestProperty("Content-Type", "application/text");
+            connection.setRequestProperty("Content-Type", "text/plain");
         } else {
             connection.setDoOutput(false);
             connection.setRequestMethod("GET");
-            connection.setRequestProperty("Content-Type", "application/text");
+            connection.setRequestProperty("Content-Type", "text/plain");
         }
 
         return connection;