title: Pig JsonLoader() bug?
body: <p>I am trying to load a json file with pig. I can load the file succesfully, but i found a bug.</p>
  
  <pre><code>schema:
  id,name,brand,color
  </code></pre>
  
  <p>data:</p>
  
  <pre><code>{"id":2561,"name":"abc","brand":"Levis","color":"Blue"}
  {"id":2562,"brand":"Adidas","color":"Black"}
  {"id":2563,"name":"edf","brand":"Nike","color":"White"}
  </code></pre>
  
  <p>code:</p>
  
  <pre><code>raw = LOAD '$INPUT_PATH' USING JsonLoader('
  id:chararray,
  name:chararray,
  brand:chararray,
  color:chararray
  ');
  
  x = foreach raw generate id,brand;
  dump x;
  </code></pre>
  
  <p>And result is wrong if the particular raw does no contains all the fields defined in the schema: (the second raw should be Adidas instead of black)</p>
  
  <pre><code>(2561,Levis)
  (2562,Black)
  (2563,Nike)
  </code></pre>
  
  <p>Is there any workaround for the above?</p>
  
  <p>thanks in advance</p>