Fix coverage configuration and execution

A number of configuration errors prevent the successful creation of code
coverage. This corrects the .coveragerc source/omit setup and the tox
package name generation.

http://lists.openstack.org/pipermail/openstack-dev/2015-October/076193.html

Change-Id: I02ba7efe7e2de15fb68fae8d6c187065ac3c60ee

.coveragerc

@@ -0,0 +1,8 @@
+[run]
+branch = True
+source = oslo_config
+omit = oslo_config/tests/*
+
+[report]
+ignore_errors = True
+precision = 2

.gitignore

@@ -7,6 +7,7 @@ ChangeLog
 *.log
 .tox
 .coverage
+cover
 oslo.config.egg-info/
 build/
 doc/build/

tox.ini

@@ -14,7 +14,7 @@ commands = flake8
 [testenv:cover]
 setenv = VIRTUAL_ENV={envdir}
 commands =
-  python setup.py testr --coverage
+  python setup.py test --coverage --coverage-package-name=oslo_config --testr-args='{posargs}'
 
 [testenv:venv]
 commands = {posargs}