fix bad URLs for Kafka and Zeppelin, fix pip install for Airflow
fix bad URLs for Kafka and Zeppelin, fix pip install for Airflow

This commit contains another raft of fixes for the bootstrap.sh
script.

The URLs for Kafka and Zeppelin refer to host www-us.apache.org
which does not retain copies of archives indefinitely.  As
new releases drop, older ones disappear. They are still accessible
by way of archive.apache.org.

    https://archive.apache.org/

Updated the hostnames and URL schemes ot use HTTPS.
Also noted that URL echoed for the kafka install
had a path error wherein the version of a
directory did not match that of a software
release (1.0.0 veruss 0.10.1.1)

    http://www-us.apache.org/dist/kafka/0.10.1.1/kafka_2.11-1.0.0.tgz

never worked at all.

The PyPi index name for Airflow is now apache-airflow. The old
name, airflow, is now a placeholder that fails upon install.
Also had to add an environment variable assignment/export
to make the install work.  Details on both of these issues
can be found here:

https://pypi.org/project/airflow/
https://cwiki.apache.org/confluence/display/AIRFLOW/Announcements#Announcements-Nov21,2018

Finally commented out a line with repeated "=" characters as it
appears to be just some spacing. It was causing "command not found
errors" by the shell.

rjurney/Agile_Data_Code_2,rjurney/Agile_Data_Code_2,rjurney/Agile_Data_Code_2,rjurney/Agile_Data_Code_2