Remove auto-create from README temporarily

Author: losfair

README.md

@@ -56,7 +56,7 @@ RUST_LOG=info ./mvstore \
   --raw-data-prefix m
 ```
 
-You can autocreate namespaces by passing the flag `--auto-create-namespace` to `mvstore` or manually create a namespace with the admin API:
+Create a namespace with the admin API:
 
 ```bash
 curl http://localhost:7001/api/create_namespace -i -d '{"key":"test"}'