Add missing parameters for CloudFront UpdateDistribution

[tomari]

CustomHeaders and QueryStringCacheKeys parameters are added to appropriate places, as they are now required for CloudFront UpdateDistribution operation.

Tested against my S3/CloudFront distribution today and works ok.

[woneill]

These changes were needed for me too. This was my first time setting this up

[MrMMorris]

for anyone else finding this, you will probably also need to add the following to the end of cf_config['DistributionConfig']['CacheBehaviors']['Items'].append:

'LambdaFunctionAssociations': {'Quantity': 0}

[k0nG]

Thanks @tomari / @MrMMorris this has helped me and is still working as of July 2017