Send a host to runner executor instead of a letter.

Discovered in #1463 .

lib/ansible/runner/__init__.py

@@ -652,7 +652,7 @@ class Runner(object):
             # We aren't iterating over all the hosts in this
             # group. So, just pick the first host in our group to
             # construct the conn object with.
-            result_data = self._executor(hosts[0][1]).result
+            result_data = self._executor(hosts[0]).result
             # Create a ResultData item for each host in this group
             # using the returned result. If we didn't do this we would
             # get false reports of dark hosts.