Supports schema revision id in avro binary formatter

Supports schema revision id in avro binary formatter

Avro formatter now supports a revision defined in schema configuration:

$wmgMonologAvroSchemas = array(
  'CirrusSearchRequestSet' => array(
    'schema' => file_get_contents( __DIR__ . '/schema.avsc' ),
    'revision' => 11144802,
  ),
);

The formatter still supports old style configuration:
$wmgMonologAvroSchemas = array(
  'CirrusSearchRequestSet' => file_get_contents( __DIR__ . '/schema.avsc' ),
);

Change-Id: Icc0f92be23305e77a69b92fee4d9f9de2edda81e