title: Chaining Delta Streams programmatically raising AnalysisException
body: <p><strong>Situation :</strong> I am producing a delta folder with data from a previous Streaming Query A, and reading later from another DF, as shown here <br></p>
  
  <pre><code>DF_OUT.writeStream.format("delta").(...).start("path")
  
  (...)
  
  DF_IN = spark.readStream.format("delta").load("path)
  </code></pre>
  
  <p><strong>1 -</strong> When I try to read it this wayin a subsequent readStream (chaining queries for an ETL Pipeline) <strong><em>from the same program</em></strong> I end up having the Exception below. </p>
  
  <p><strong>2 -</strong> When I run it in the scala REPL however, it runs smoothly. <br>
  Not sure What is happening there but it sure is puzzling. </p>
  
  <pre><code>org.apache.spark.sql.AnalysisException: Table schema is not set.  Write data into it or use CREATE TABLE to set the schema.;
    at org.apache.spark.sql.delta.DeltaErrors$.schemaNotSetException(DeltaErrors.scala:365)
    at org.apache.spark.sql.delta.sources.DeltaDataSource.sourceSchema(DeltaDataSource.scala:74)
    at org.apache.spark.sql.execution.datasources.DataSource.sourceSchema(DataSource.scala:209)
    at org.apache.spark.sql.execution.datasources.DataSource.sourceInfo$lzycompute(DataSource.scala:95)
    at org.apache.spark.sql.execution.datasources.DataSource.sourceInfo(DataSource.scala:95)
    at org.apache.spark.sql.execution.streaming.StreamingRelation$.apply(StreamingRelation.scala:33)
    at org.apache.spark.sql.streaming.DataStreamReader.load(DataStreamReader.scala:171)
    at org.apache.spark.sql.streaming.DataStreamReader.load(DataStreamReader.scala:225)
    at org.apache.spark.ui.DeltaPipeline$.main(DeltaPipeline.scala:114)
  
  </code></pre>