Rebuild for sync layer-openstack

Also explicitly set ``include_system_packages`` to False.

While that setting is now the a default we consume from
``layer-basic`` it is more clear for the causual reader
of the charm source code.

Remove redundant entries from ``wheelhouse.txt``.

Change-Id: Id3d40ad97791d6c10b54570fd02b6eb401a69063

rebuild

@@ -2,4 +2,4 @@
 # when dependencies of the charm change,
 # but nothing in the charm needs to.
 # simply change the uuid to something new
-6a4e8d66-b54e-11e9-9e21-27ae1864b062
+f57f307b-74f9-4f1d-bdc2-50e20aecbb63

src/layer.yaml

@@ -6,4 +6,5 @@ includes:
   - interface:nova-cell
 options:
   basic:
-    use_venv: true
+    use_venv: True
+    include_system_packages: False

src/wheelhouse.txt

@@ -1,3 +0,0 @@
-
-jinja2
-psutil