test_fixtures: Include LOCAL_DATABASE_PASSWORD in digest.

This ensures that if one deletes `zproject/dev-secrets.conf`, we end
up rebuilding the databases from scratch (which, critically, will
ensure the password that gets setup matches what's in the current
version of the configuration file).

This should address a category of issue we've had where deleting
`zproject/dev-secrets.conf` would result in provision failing.

zerver/lib/test_fixtures.py

@@ -79,6 +79,7 @@ class Database:
             return json.dumps(value, sort_keys=True)
 
         return [
+            get('LOCAL_DATABASE_PASSWORD'),
             get('INTERNAL_BOTS'),
             get('REALM_INTERNAL_BOTS'),
             get('DISABLED_REALM_INTERNAL_BOTS'),