Cant load model from path with 1.6
I have a 1.6 model trying to load with the following line:

`nemo_asr.models.EncDecCTCModelBPE.restore_from`

And I get this:

```
[NeMo E 2022-03-11 17:35:11 common:504] Traceback (most recent call last):
      File "/root/.cache/pypoetry/virtualenvs/--IulmO6hw-py3.7/lib/python3.7/site-packages/nemo/core/classes/common.py", line 477, in from_config_dict
        instance = imported_cls(cfg=config, trainer=trainer)
      File "/root/.cache/pypoetry/virtualenvs/--IulmO6hw-py3.7/lib/python3.7/site-packages/nemo/collections/asr/models/ctc_bpe_models.py", line 194, in __init__
        self._setup_tokenizer(cfg.tokenizer)
      File "/root/.cache/pypoetry/virtualenvs/--IulmO6hw-py3.7/lib/python3.7/site-packages/nemo/collections/asr/parts/mixins/mixins.py", line 84, in _setup_tokenizer
        self.tokenizer = tokenizers.SentencePieceTokenizer(model_path=model_path)
      File "/root/.cache/pypoetry/virtualenvs/--IulmO6hw-py3.7/lib/python3.7/site-packages/nemo/utils/exceptions.py", line 31, in __init__
        raise LightningNotInstalledException(self)
    nemo.utils.exceptions.LightningNotInstalledException:  You are trying to use <nemo.collections.common.tokenizers.SentencePieceTokenizer object at 0x7f582a0ad950> without installing all of pytorch_lightning, hydra, and omegaconf. Please install those packages before trying to access <nemo.collections.common.tokenizers.SentencePieceTokenizer object at 0x7f582a0ad950>.
    
```

All there of those packages are installed and importable 