ImportError when running the latest awscli with Python 1.7.15rc1

```

talonx>% sudo -H pip install awscli   

Collecting awscli

  Using cached https://files.pythonhosted.org/packages/87/59/895121a6278c21e77b2aeddc23bf54b10486f0e641553672b765043834db/awscli-1.16.7-py2.py3-none-any.whl

Requirement already satisfied: docutils>=0.10 in /usr/local/lib/python2.7/dist-packages (from awscli) (0.13.1)

Collecting botocore==1.11.7 (from awscli)

  Using cached https://files.pythonhosted.org/packages/55/fd/99b9962da5e4ed41754aa23a6e030e4b2b844120edcb52a83124dc0af087/botocore-1.11.7-py2.py3-none-any.whl

Requirement already satisfied: PyYAML<=3.13,>=3.10 in /usr/lib/python2.7/dist-packages (from awscli) (3.12)

Requirement already satisfied: rsa<=3.5.0,>=3.1.2 in /usr/local/lib/python2.7/dist-packages (from awscli) (3.4.2)

Requirement already satisfied: colorama<=0.3.9,>=0.2.5 in /usr/lib/python2.7/dist-packages (from awscli) (0.3.7)

Requirement already satisfied: s3transfer<0.2.0,>=0.1.12 in /usr/local/lib/python2.7/dist-packages (from awscli) (0.1.13)

Requirement already satisfied: jmespath<1.0.0,>=0.7.1 in /usr/local/lib/python2.7/dist-packages (from botocore==1.11.7->awscli) (0.9.3)

Requirement already satisfied: python-dateutil<3.0.0,>=2.1; python_version >= "2.7" in /usr/local/lib/python2.7/dist-packages (from botocore==1.11.7->awscli) (2.6.1)

Requirement already satisfied: urllib3<1.24,>=1.20 in /usr/local/lib/python2.7/dist-packages (from botocore==1.11.7->awscli) (1.22)

Requirement already satisfied: pyasn1>=0.1.3 in /usr/local/lib/python2.7/dist-packages (from rsa<=3.5.0,>=3.1.2->awscli) (0.4.4)

Requirement already satisfied: futures<4.0.0,>=2.2.0; python_version == "2.6" or python_version == "2.7" in /usr/local/lib/python2.7/dist-packages (from s3transfer<0.2.0,>=0.1.12->awscli) (3.2.0)

Requirement already satisfied: six>=1.5 in /usr/lib/python2.7/dist-packages (from python-dateutil<3.0.0,>=2.1; python_version >= "2.7"->botocore==1.11.7->awscli) (1.11.0)

Installing collected packages: botocore, awscli

Successfully installed awscli-1.16.7 botocore-1.11.7

talonx>% aws

Traceback (most recent call last):

  File "/usr/local/bin/aws", line 19, in <module>

    import awscli.clidriver

  File "/usr/local/lib/python2.7/dist-packages/awscli/clidriver.py", line 19, in <module>

    from botocore.hooks import AliasedEventEmitter

ImportError: cannot import name AliasedEventEmitter

```

Python 2.7.15rc1 on Ubuntu 18.04.1 LTS

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