S3Boto3Storage: Fix _get_or_create_bucket

[linuxlewis]

The current implementation throws an ImproperlyConfigured error instead of creating the bucket. This occurs even when AWS_AUTO_CREATE_BUCKET has been set to true.

[codecov-io]

Current coverage is 59.32% (diff: 0.00%)

Merging #196 into master will decrease coverage by 0.03%

@@             master       #196   diff @@
==========================================
  Files            17         17          
  Lines          1693       1694     +1   
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
  Hits           1005       1005          
- Misses          688        689     +1   
  Partials          0          0          

Powered by Codecov. Last update 9bd76bc...3b22fde

[jschneier]

Hi and thanks for the PR! My one point of concern is that we are now calling .head_bucket unconditionally which would add more calls (that people pay for!). Do you have any thoughts on that?

[linuxlewis]

@jschneier I updated the PR to address your concerns. Are head requests actually charged for? I couldn't find them on the pricing page: https://aws.amazon.com/s3/pricing/

[jschneier]

I assume that it's contained within this:

GET and all other Requests $0.004 per 10,000 requests

[jschneier]

Thanks, merged