Add `myria` namespace package to package metadata

[senderista]

Currently myria-cluster conflicts with myria-python because both packages define modules in the same root namespace myria. The solution should be for both packages to add the "namespace package" myria to their package metadata: http://setuptools.readthedocs.io/en/latest/setuptools.html#namespace-packages.

This requires that all packages sharing the same "root namespace" separately declare it in setup.py as a "namespace package":

setup(
    # ...
    namespace_packages = ['myria']
)

In the __init__.py corresponding to the namespace package:

__import__('pkg_resources').declare_namespace(__name__)

[BrandonHaynes]

Fixed in ac641e0

[senderista]

I've been trying to verify this fix with my own identical fix in myria-ec2-ansible, but haven't managed to get it working. This suggests that the problem is additional code in myria/__init__.py:

You must NOT include any other code and data in a namespace package’s init.py. Even though it may appear to work during development, or when projects are installed as .egg files, it will not work when the projects are installed using “system” packaging tools – in such cases the init.py files will not be installed, let alone executed.

[BrandonHaynes]

Removing this may break compatibility with existing code, but I don't see an immediate workaround.