Add a warning about include + with_items so nobody uses it.

lib/ansible/playbook/play.py

@@ -24,6 +24,7 @@ from ansible.playbook.task import Task
 import pipes
 import shlex
 import os
+import sys
 
 class Play(object):
 
@@ -426,6 +427,7 @@ class Play(object):
                 include_vars = {}
                 for k in x:
                     if k.startswith("with_"):
+                        sys.stderr.write("DEPRECATION: include + with_items is unsupported/undocumented and will be removed in Ansible 1.5, it will likely not do what you think it does.\n")
                         plugin_name = k[5:]
                         if plugin_name not in utils.plugins.lookup_loader:
                             raise errors.AnsibleError("cannot find lookup plugin named %s for usage in with_%s" % (plugin_name, plugin_name))