Apply localhost workaround if ansible_host is localhost

This shouldn't really ever happen for real in zuul, but just in case we
do something in a trusted playbook somewhere like setting ansible_host
to localhost, the code should at least do the right thing. (This comes
up more in doing local testing of plugins)

Change-Id: I638fa5f8cd69cd46823ea42bc4e257972d125945
diff --git a/zuul/ansible/callback/zuul_stream.py b/zuul/ansible/callback/zuul_stream.py
index 6d27f15..c6cc7ab 100644
--- a/zuul/ansible/callback/zuul_stream.py
+++ b/zuul/ansible/callback/zuul_stream.py
@@ -172,6 +172,9 @@
                 ip = play_vars[host].get(
                     'ansible_host', play_vars[host].get(
                         'ansible_inventory_host'))
+                if ip in ('localhost', '127.0.0.1'):
+                    # Don't try to stream from localhost
+                    continue
                 streamer = threading.Thread(
                     target=self._read_log, args=(
                         host, ip, log_id, task_name, hosts))