Cleanup and fix Tacker coverage

Test classes were being accounted for during coverage, they
are now ignored for more accurate coverage metrics. Remove
references to neutron in .coveragerc. Fix tox.ini coverage
entry.

Co-Authored-By: Larry Rensing <lr699s@att.com>
Co-Authored-By: Sridhar Ramaswamy <srics.r@gmail.com>

Change-Id: I92d50592a5ba43f68554aa933ab8582897b58b43

.coveragerc

@@ -1,7 +1,7 @@
 [run]
 branch = True
-source = neutron
-omit = neutron/tests/*,neutron/plugins/cisco/test/*,neutron/openstack/*
+source = tacker
+omit = tacker/tests/*
 
 [report]
 ignore_errors = True

tox.ini

@@ -54,8 +54,17 @@ commands =
     python setup.py build_sphinx
 
 [testenv:cover]
+# Also do not run test_coverage_ext tests while gathering coverage as those
+# tests conflict with coverage.
+# NOTE(sdague): this target does not use constraints because
+# upstream infra does not yet support it. Once that's fixed, we can
+# drop the install_command.
+install_command = pip install -U --force-reinstall {opts} {packages}
 commands =
-  python -m tacker.openstack.common.lockutils python setup.py testr --coverage --testr-args='{posargs}'
+  coverage erase
+  python setup.py testr --coverage --testr-args='{posargs}'
+  coverage combine
+  coverage html --include='tacker/*' -d covhtml -i
 
 [testenv:venv]
 commands = {posargs}