Log Message:
Changes in Apache Libcloud 2.1.0

Common
- [AWS] Update prices and fix some region names
- Fix bug in utils.decorators wrap exception method, used by vsphere driver
- Use PyTest as the unit testing runner
- Use of LXML is now disabled by defalt, use libcloud.utils.py3.DEFAULT_LXML = \ 
True to reenable. LXML has compatibility
  issues with a number of drivers and etree is a standard package
- Switch RawResponse class to use content body instead of text body, up to 10x \ 
performance improvement for methods like StorageDriver.download_object