Add some ansible plugin tests

This is not complete, but it's a start.

While doing this it became clear that the upstream csvfile lookup plugin does
not work in python3. Work around that by putting in a simpler version of
the code into our copy.

Change-Id: Ic84d8265e6fd7e15a0e5d66c781409a087d761d7
diff --git a/tests/fixtures/config/ansible/main.yaml b/tests/fixtures/config/ansible/main.yaml
index 9ccece9..a4e32c2 100644
--- a/tests/fixtures/config/ansible/main.yaml
+++ b/tests/fixtures/config/ansible/main.yaml
@@ -6,4 +6,5 @@
           - common-config
         untrusted-projects:
           - org/project
+          - org/plugin-project
           - bare-role