CDAP-15492 Salesforce streaming integration tests fail, jar includes unnecessary Spark

[aonischuk]

1. Streaming integration tests fail with:

testValuesReturned(io.cdap.plugin.salesforce.etl.SalesforceStreamingSourceETLTest)  Time elapsed: 5.255 sec  <<< ERROR!
 java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.ExceptionInInitializerError
     at com.fasterxml.jackson.module.scala.JacksonModule$class.setupModule(JacksonModule.scala:64)
     at com.fasterxml.jackson.module.scala.DefaultScalaModule.setupModule(DefaultScalaModule.scala:19)
     at com.fasterxml.jackson.databind.ObjectMapper.registerModule(ObjectMapper.java:751)
     at org.apache.spark.rdd.RDDOperationScope$.<init>(RDDOperationScope.scala:82)
     at org.apache.spark.rdd.RDDOperationScope$.<clinit>(RDDOperationScope.scala)
     at org.apache.spark.streaming.StreamingContext.withNamedScope(StreamingContext.scala:273)
     at org.apache.spark.streaming.StreamingContext.receiverStream(StreamingContext.scala:282)
     at org.apache.spark.streaming.api.java.JavaStreamingContext.receiverStream(JavaStreamingContext.scala:428)
     at io.cdap.plugin.salesforce.plugin.source.streaming.SalesforceStreamingSource.getStream(SalesforceStreamingSource.java:115)
     at io.cdap.cdap.etl.spark.plugin.WrappedStreamingSource$2.call(WrappedStreamingSource.java:59)
     ...

This happens because com.fasterxml.jackson.core/jackson-databind 2.6.7 is used by org.apache.spark/spark-core_2.11. While with the patch we use 2.9.9.
So I guess when we classload all the classes into a single scope wrong jackson-databind gets loaded, causing spark to fail.
2. Salesforce jar has size of 32Mb currently. Without spark core which is provided by CDAP, therefore unnecessary, it has size of 9Mb.
3. Fix a wrong default value for SFDC widget causing "unknown value" problems.

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[aonischuk]

@albertshau do you think we should keep the jira open after this is merged? I cannot see any viable solution for this though.

[albertshau]

lgtm. Yes let's keep the jira open so we don't lose it.

[albertshau]

don't think we can package this version. Can you try updating spark to a version that uses a newer jackson? If that doesn't work, since you mentioned this only breaks the test and not the actual plugin, let's add a note about overriding this when running the test and keep an jira open for fixing this.