[wip] Let jsonfile and memcached cache plugins understand fact_caching_timeout=0 (#17565)

* Add support for no-expiration to jsonfile cache

* Let memcached cache use fact_caching_timeout=0

If fact_cache=memcached and fact_caching_timeout=0
memcached would hit a NameError on _expire_keys

lib/ansible/plugins/cache/jsonfile.py

@@ -108,6 +108,9 @@ class CacheModule(BaseCacheModule):
 
     def has_expired(self, key):
 
+        if self._timeout == 0:
+            return False
+
         cachefile = "%s/%s" % (self._cache_dir, key)
         try:
             st = os.stat(cachefile)

lib/ansible/plugins/cache/memcached.py

@@ -157,7 +157,7 @@ class CacheModule(BaseCacheModule):
     def _expire_keys(self):
         if self._timeout > 0:
             expiry_age = time.time() - self._timeout
-        self._keys.remove_by_timerange(0, expiry_age)
+            self._keys.remove_by_timerange(0, expiry_age)
 
     def get(self, key):
         value = self._cache.get(self._make_key(key))