Merge pull request #12695 from matburt/fix_cache_plugins_for_v2

Fix an issue where cache plugins weren't updated in certain scenarios

lib/ansible/plugins/cache/__init__.py

@@ -68,3 +68,8 @@ class FactCache(MutableMapping):
     def flush(self):
         """ Flush the fact cache of all keys. """
         self._plugin.flush()
+
+    def update(self, key, value):
+        host_cache = self._plugin.get(key)
+        host_cache.update(value)
+        self._plugin.set(key, host_cache)

lib/ansible/vars/__init__.py

@@ -546,7 +546,7 @@ class VariableManager:
             self._fact_cache[host.name] = facts
         else:
             try:
-                self._fact_cache[host.name].update(facts)
+                self._fact_cache.update(host.name, facts)
             except KeyError:
                 self._fact_cache[host.name] = facts