`az --version` fails with SyntaxError on Python 3

Description

az --version fails with SyntaxError on Python 3 due to Python 2 only library futures being installed.

Installing azure-cli 2.0.10 with pip on Python 3.6.1 produces this output. Importantly, these lines appear:

Collecting futures (from azure-multiapi-storage==0.1.0->azure-cli-vm->azure-cli)
  Downloading futures-3.1.1.tar.gz

Subsequently, operations in that environment that require pip will fail when compileall, which imports concurrent, is imported. For example:

$ PYTHONPATH=/opt/azure python -c "import pip"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/opt/azure/pip/__init__.py", line 28, in <module>
    from pip.vcs import git, mercurial, subversion, bazaar  # noqa
  File "/opt/azure/pip/vcs/subversion.py", line 9, in <module>
    from pip.index import Link
  File "/opt/azure/pip/index.py", line 31, in <module>
    from pip.wheel import Wheel, wheel_ext
  File "/opt/azure/pip/wheel.py", line 6, in <module>
    import compileall
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/compileall.py", line 20, in <module>
    from concurrent.futures import ProcessPoolExecutor
  File "/opt/azure/concurrent/futures/__init__.py", line 8, in <module>
    from concurrent.futures._base import (FIRST_COMPLETED,
  File "/opt/azure/concurrent/futures/_base.py", line 381
    raise exception_type, self._exception, self._traceback
                        ^
SyntaxError: invalid syntax

A similar traceback will appear with az --version when it imports pip.

Futures declares that it’s Python 2 only, so shouldn’t be installed on Python 3.

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Environment summary

Install Method: How did you install the CLI? (e.g. pip, interactive script, apt-get, Docker, MSI, nightly)
Answer here: pip

CLI Version: What version of the CLI and modules are installed? (Use az --version)
Answer here: 2.0.10

OS Version: What OS and version are you using?
Answer here: macOS 10.12.5

Shell Type: What shell are you using? (e.g. bash, cmd.exe, Bash on Windows)
Answer here: zsh

[jaraco]

I was able to work around the issue by manually removing the concurrent package and then uninstalling futures.

$ rm -R /opt/azure/concurrent
$ PYTHONPATH=/opt/azure python -m pip uninstall -y futures
Uninstalling futures-3.1.1:
  Successfully uninstalled futures-3.1.1

[jiasli]

@afelthe, Azure CLI has dropped support for Python 2 (https://github.com/Azure/azure-cli/pull/11363). Are you using the latest Azure CLI?