[SPARK-23695][PYTHON] Fix the error message for Kinesis streaming tests

[HyukjinKwon]

What changes were proposed in this pull request?

This PR proposes to fix the error message for Kinesis in PySpark when its jar is missing but explicitly enabled.

ENABLE_KINESIS_TESTS=1 SPARK_TESTING=1 bin/pyspark pyspark.streaming.tests

Before:

Skipped test_flume_stream (enable by setting environment variable ENABLE_FLUME_TESTS=1Skipped test_kafka_stream (enable by setting environment variable ENABLE_KAFKA_0_8_TESTS=1Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 174, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/.../spark/python/pyspark/streaming/tests.py", line 1572, in <module>
    % kinesis_asl_assembly_dir) +
NameError: name 'kinesis_asl_assembly_dir' is not defined

After:

Skipped test_flume_stream (enable by setting environment variable ENABLE_FLUME_TESTS=1Skipped test_kafka_stream (enable by setting environment variable ENABLE_KAFKA_0_8_TESTS=1Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 174, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/.../spark/python/pyspark/streaming/tests.py", line 1576, in <module>
    "You need to build Spark with 'build/sbt -Pkinesis-asl "
Exception: Failed to find Spark Streaming Kinesis assembly jar in /.../spark/external/kinesis-asl-assembly. You need to build Spark with 'build/sbt -Pkinesis-asl assembly/package streaming-kinesis-asl-assembly/assembly'or 'build/mvn -Pkinesis-asl package' before running this test.

How was this patch tested?

Manually tested.

[HyukjinKwon]

cc @ueshin

[SparkQA]

Test build #88265 has finished for PR 20834 at commit d2fe1e9.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[ueshin]

LGTM.

[ueshin]

Thanks! merging to master/2.3.

[HyukjinKwon]

Thank you @ueshin.