Mark glance_store as being a universal wheel

Universal is used to identify pure-Python module(by bdist_wheel).
For these, it is sufficient to build a wheel with _any_ Python ABI
version and publish that to PyPI (by whatever means).

Change-Id: I40d66609277e58e8d6fee9cc98948f7b2507f75a
Merge "Mark glance_store as being a universal wheel"