The tox coverage refers to a non-existing rc file. This patch set
redresses this by putting in a proper .coveragerc file similar to
all the other projects.
This patchset also makes the tox coverage job compatible w/ Zuul.
Change-Id: I96a3d13482053b591f7d01e1c5c1e906d84f8fb7
Depends-On: If3cba68492ba9c7a0e78258c7b669d1b39fcdeba
Signed-off-by: Tin Lam <tin@irrational.io>