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: I74d2af73a57ba72631e5eea3ace3275c0b349352

.coveragerc

@@ -1,7 +1,8 @@
 [run]
 branch = True
-source = context
+source = oslo_context
-omit = context/tests/*,context/openstack/*
+omit = oslo_context/tests/*
 
 [report]
 ignore_errors = True
+precision = 2

.gitignore

@@ -23,6 +23,7 @@ pip-log.txt
 
 # Unit test / coverage reports
 .coverage
+cover
 .tox
 nosetests.xml
 .testrepository

tox.ini

@@ -26,7 +26,7 @@ commands = {posargs}
 commands = python setup.py build_sphinx
 
 [testenv:cover]
-commands = python setup.py testr --coverage --testr-args='{posargs}'
+commands = python setup.py test --coverage --coverage-package-name=oslo_context --testr-args='{posargs}'
 
 [flake8]
 # H803 skipped on purpose per list discussion.