Fix testing with Python3

[mvanderlee]

What changes were proposed in this pull request?

Fix print statement in tests to be Python 2 and Python 3 compatible.
#408

Created an account in JIRA, waiting for approval so I can submit a ticket there as well.

How was this patch tested?

Using the docker build for Spark 3

docker run --rm -it -v $(pwd):/workspace -v $HOME/.m2:/root/.m2 livy-ci mvn package -Pspark3 

[codecov-commenter]

Codecov Report

Merging #424 (5271a3a) into master (8b2e29f) will decrease coverage by 36.91%.
The diff coverage is n/a.

@@              Coverage Diff              @@
##             master     #424       +/-   ##
=============================================
- Coverage     65.48%   28.58%   -36.91%     
+ Complexity      950      378      -572     
=============================================
  Files           103      103               
  Lines          6062     6062               
  Branches        916      916               
=============================================
- Hits           3970     1733     -2237     
- Misses         1541     3976     +2435     
+ Partials        551      353      -198     

see 86 files with indirect coverage changes

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[ksumit]

Thanks @mvanderlee for your contribution.