DNM force etherpad failure to hold node

We want to upgrade to etherpad 2.0.3. This will hold the node for
sanity checking.

Change-Id: I553f628fff9a9476efbe32aaf81e3aa131484ade

testinfra/test_etherpad.py

@@ -156,3 +156,6 @@ def test_etherpad_restore_pad(host):
     assert '"message":"ok"' in cmd.stdout
     assert firststr in cmd.stdout
     assert secondstr not in cmd.stdout
+
+def test_etherpad_force_fail(host):
+    assert False