Description of problem:
AWS users who had the Fedora EPEL copy of awscli installed prior to the update to RHEL 7.5 are left with a non-functional aws command when yum update'd to 7.5.

Version-Release number of selected component (if applicable):
awscli-1.14.28-5.el7

How reproducible:
Always

Steps to Reproduce:
1. Install EPEL copy of awscli-1.11.133-1.el7 package to reproduce what an existing user will already have. This pulls in python-colorama python-docutils python-pillow python2-botocore python2-futures python2-jmespath python2-rsa python2-s3transfer
2. `yum update awscli` to pull in base copy of awscli at 1.14.28-5.el7
3. Run `aws` 

Actual results:
aws produces stacktrace and dies:

# aws
Traceback (most recent call last):
  File "/bin/aws", line 19, in <module>
    import awscli.clidriver
  File "/usr/lib/python2.7/site-packages/awscli/clidriver.py", line 25, in <module>
    from botocore.history import get_global_history_recorder
ImportError: No module named history

After `yum swap python2-s3transfer python-s3transfer` the aws command functions as expected.


Expected results:
aws command works

Additional info:
The problem is due to incompatible python2-s3transfer vs python-s3transfer packages. All existing awscli users will be left with a non-functional command after the yum update to the RHEL base copy. Running `yum swap python2-s3transfer python-s3transfer` will fix this but ideally it would be better not to break things in the first place. I suspect the best solution to this would be for awscli to Require: python-s3transfer directly or for python-s3transfer to Obsolete: python2-s3transfer.