MINOR: Fix integration tests by adding datafusion-cli module to docker image

[andygrove]

The recent changes to move DataFusion CLI to a separate crate broke the Ballista integration tests. This PR simply adds this crate to the Docker image used by the integration tests.

For anyone that is interested, integration tests can be run with this command:

./dev/integration-tests.sh

I filed apache/datafusion-ballista#24 for adding these tests to CI

[codecov-commenter]

Codecov Report

Merging #322 (ca42d33) into master (a1c6898) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     apache/arrow-datafusion#322   +/-   ##
=======================================
  Coverage   76.19%   76.19%           
=======================================
  Files         141      141           
  Lines       23786    23786           
=======================================
  Hits        18123    18123           
  Misses       5663     5663           

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[alamb]

Looks good to me. I didn't test it but 👍