Fix and Gate on H303 (no wildcard imports)

Wildcard imports make reading code unnecessarily confusing because they
make it harder to see where a functions comes from.  We had two types of
wildcard imports in the code. Unneeded ones in test files that are just
removed, and some that we actually want which are kept using the '#
noqa' comment to tell flake8 to skip specific checks (such as H303)
for that line.

Change-Id: Id4705011579659fd74a4aaa05ac541e9694c483e

nova/tests/scheduler/__init__.py

@@ -14,6 +14,3 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-
-# NOTE(vish): this forces the fixtures from tests/__init.py:setup() to work
-from nova.tests import *