Display coverage report

... for easy reference. Also make sure old data is purged.

This also fixes the missing coverage command, and the wrong option in
.coveragerc .

Change-Id: I7d4dcaea2e42d564c8f4264aecd15588085d63e3

.coveragerc

@@ -4,4 +4,4 @@ source = oslo_privsep
 omit = oslo_privsep/tests/*
 
 [report]
-ignore-errors = True
+ignore_errors = True

tox.ini

@@ -33,13 +33,17 @@ commands =
   sphinx-build -W --keep-going -b html doc/source doc/build/html
 
 [testenv:cover]
+deps = {[testenv]deps}
+    coverage
 setenv =
-    PYTHON=coverage run --source $project --parallel-mode
+    PYTHON=coverage run --source oslo_privsep --parallel-mode
 commands =
+    coverage erase
     stestr run {posargs}
     coverage combine
     coverage html -d cover
     coverage xml -o cover/coverage.xml
+    coverage report --show-missing
 
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.