Add health_check_interval to avoid connection reset (#2259)

Co-authored-by: Kyle Ju <kyleju@chromium.org>

framework/rediscache.py

@@ -31,7 +31,7 @@ elif settings.STAGING or settings.PROD:
   # Create a Redis client.
   redis_host = os.environ.get('REDISHOST', 'localhost')
   redis_port = int(os.environ.get('REDISPORT', 6379))
-  redis_client = redis.Redis(host=redis_host, port=redis_port)
+  redis_client = redis.Redis(host=redis_host, port=redis_port, health_check_interval=30)
 
 gae_version = None
 if settings.UNIT_TEST_MODE: