title: There is no data in ksql table after creating a table on a kafka topic
body: <p>I'm trying to create a ksql table from an existing topic in kafka.
  When I query the table no data is showing up.</p>
  
  <p>I tried producing the messages to kafka topic with keys. Those are visible in a ksql stream I created, But when I create a similar table there is no data in the table.</p>
  
  <p>Producing the data:</p>
  
  <pre><code>sh kafka-console-producer \
  --broker-list kf-pranay-kafka-0.kf-pranay-kafka-headless.default.svc.cluster.local:9092 \
  --topic ppp \
  --property "parse.key=true" \
  --property "key.separator=:"
  1:{"sr":"1","title":"The Matrix","year":1999,"genres":"Science Fiction"}
  2:{"sr":"2","title":"Die Hard","year":1988,"genres":"Action"}
  3:{"sr":"3","title":"Toy Story","year":1995,"genres":"Animated"}
  </code></pre>
  
  <p>Creating and querying a stream:</p>
  
  <pre><code>ksql&gt; SET 'auto.offset.reset'='earliest';
  Successfully changed local property 'auto.offset.reset' from 'earliest' to 'earliest'.
  ksql&gt;
  ksql&gt; CREATE STREAM ppp (sr varchar, title varchar, year bigint, genres varchar) WITH
  &gt;(kafka_topic='ppp', value_format='JSON');
  
   Message
  ----------------
   Stream created
  ----------------
  ksql&gt;
  ksql&gt; SELECT * FROM ppp;
  1560340201759 | 1 | 1 | The Matrix | 1999 | Science Fiction
  1560340201767 | 2 | 2 | Die Hard | 1988 | Action
  1560340201767 | 3 | 3 | Toy Story | 1995 | Animated
  ^CQuery terminated
  ksql&gt;
  ksql&gt; CREATE TABLE movie_table (sr varchar, title varchar, year bigint, genres varchar) WITH
  &gt;(kafka_topic='ppp', value_format='JSON', key = 'sr');
  
   Message
  ---------------
   Table created
  ---------------
  ksql&gt;
  ksql&gt; SELECT * FROM MOVIE_TABLE;
  ^CQuery terminated
  </code></pre>
  
  <p>I am expecting a similar output from table as SELECT query from a STREAM. But it seems I am not getting any data in the table.</p>