Fix duplicate host with different uuid created after add_host

If add_host is performed with hostname existing in inventory, but
not yet accessed and put in inventory cache, additional host with
same hostname and different uuid is created, causing patterns to
misbehave.

lib/ansible/plugins/strategy/__init__.py

@@ -399,10 +399,9 @@ class StrategyBase:
 
         host_name = host_info.get('host_name')
 
-        # Check if host in cache, add if not
-        if host_name in self._inventory._hosts_cache:
-            new_host = self._inventory._hosts_cache[host_name]
-        else:
+        # Check if host in inventory, add if not
+        new_host = self._inventory.get_host(host_name)
+        if not new_host:
             new_host = Host(name=host_name)
             self._inventory._hosts_cache[host_name] = new_host