IMPALA-9627: Update utility scripts for Python 3 (part 2)

We're starting to see environments where the system Python ('python') is
Python 3. Updates utility and build scripts to work with Python 3, and
updates check-pylint-py3k.sh to check scripts that use system python.

Fixes other issues found during a full build and test run with Python
3.8 as the default for 'python'.

Fixes a impala-shell tip that was supposed to have been two tips (and
had no space after period when they were printed).

Removes out-of-date deploy.py and various Python 2.6 workarounds.

Testing:
- Full build with /usr/bin/python pointed to python3
- run-all-tests passed with python pointed to python3
- ran push_to_asf.py

Change-Id: Idff388aff33817b0629347f5843ec34c78f0d0cb
Reviewed-on: http://gerrit.cloudera.org:8080/19697
Reviewed-by: Michael Smith <michael.smith@cloudera.com>
Tested-by: Michael Smith <michael.smith@cloudera.com>

bin/gen-backend-test-script.py

@@ -20,6 +20,7 @@
 # used by the build system (see be/CMakeLists.txt for usage) and is not intended to be
 # run directly.
 
+from __future__ import absolute_import, division, print_function
 import argparse
 import os
 import stat