hparam_overrides not working
🐛 Bug
Error when using hparam_overrides which was recently introduced by: #1797. This is the log:
Traceback (most recent call last):
  File "main.py", line 211, in <module>
    model = RelationEmbeddingModelLit.load_from_checkpoint(
  File "/home/ubuntu/anaconda3/envs/py38/lib/python3.8/site-packages/pytorch_lightning/core/lightning.py", line 1601, in load_from_checkpoint
    update_hparams(hparams, hparam_overrides)
UnboundLocalError: local variable 'hparams' referenced before assignment

To Reproduce
Steps to reproduce the behavior:

Load a checkpoint using the hparam_overrides argument:

MyPLModel.load_from_checkpoint(checkpoint_path, hparam_overrides={key: new_val})

Expected behavior
No bug.
Environment

CUDA:

GPU:

Tesla V100-SXM2-16GB


available:         True
version:           10.1


Packages:

numpy:             1.18.1
pyTorch_debug:     False
pyTorch_version:   1.4.0
pytorch-lightning: 0.7.7-dev
tensorboard:       2.2.1
tqdm:              4.43.0


System:

OS:                Linux
architecture:

64bit
ELF


processor:         x86_64
python:            3.8.1
version:           #117-Ubuntu SMP Wed Apr 8 09:52:02 UTC 2020