Fix wheel METADATA and ensure conditional dependencies are handled correctly.
Fix wheel METADATA and ensure conditional dependencies are handled
correctly.

This is needed because we use universal wheel (same wheel for Python 2
and Python 3) and some dependencies are only needed under some Python
versions.

Implementation should also work with older setuptools and pip versions
locally.

For committers - we need to use newer version of setuptools to ensure
generated wheel contains correct metadata.

apache/libcloud,mistio/libcloud,mistio/libcloud,apache/libcloud,andrewsomething/libcloud,andrewsomething/libcloud,apache/libcloud,Kami/libcloud,andrewsomething/libcloud,Kami/libcloud,mistio/libcloud,Kami/libcloud