Make default func27-smoke xenial-pike

Change-Id: I7c202d994c48e147daee5a3be30a0f1dd4e1ecc5

src/tox.ini

@@ -35,7 +35,7 @@ commands =
 # Run a specific test as an Amulet smoke test (expected to always pass)
 basepython = python2.7
 commands =
-    bundletester -vl DEBUG -r json -o func-results.json gate-basic-xenial-ocata --no-destroy
+    bundletester -vl DEBUG -r json -o func-results.json gate-basic-xenial-pike --no-destroy
 
 [testenv:func27-dfs]
 # Run all deploy-from-source tests which are +x (may not always pass!)