title: spark.cassandra.input.split.size_in_mb is not a valid Spark Cassandra Connector variable
body: <p>I have been using <a href="https://github.com/TargetHolding/pyspark-cassandra" rel="nofollow noreferrer">pyspark-cassandra 0.1.5</a> with spark 1.4.1(latest release).</p>
  
  <p>But normal counting of 1519784 records of cassandra is taking 70 secs.</p>
  
  <p>From <a href="https://stackoverflow.com/questions/31583249/apache-spark-taking-5-to-6-minutes-for-simple-count-of-1-billon-rows-from-cassan?lq=1">this</a> question in stackoverflow, I came to know about the use of "<strong>spark.cassandra.input.split.size_in_mb</strong>" while defining SparkConf, will help in reducing the time.</p>
  
  <p>But i get the following error, while including the same in my python code</p>
  
  <pre><code>py4j.protocol.Py4JJavaError: An error occurred while calling o93.cassandraTable.
  : com.datastax.spark.connector.util.ConfigCheck$ConnectorConfigurationException: Invalid Config Variables
  Only known spark.cassandra.* variables are allowed when using the Spark Cassandra Connector.
  spark.cassandra.input.split.size_in_mb is not a valid Spark Cassandra Connector variable.
  Possible matches:
  spark.cassandra.input.split.size
  </code></pre>
  
  <p>I believe I am doing something silly. I am very new to Spark, please help.</p>