Uncenssary information of apex always pop up
🐛 Bug

To Reproduce
import pytorch_lightning as pl
trainer = pl.Trainer(
    gpus=2,
    progress_bar_refresh_rate=0,
    precision=16,
    num_sanity_val_steps=0,
    profiler=True,
    gradient_clip_val=hparams.gradient_clip_val,
)

output:
Selected optimization level O1:  Insert automatic casts around Pytorch functions and Tensor methods.

Defaults for this optimization level are:
enabled                : True
opt_level              : O1
cast_model_type        : None
patch_torch_functions  : True
keep_batchnorm_fp32    : None
master_weights         : None
loss_scale             : dynamic
Processing user overrides (additional kwargs that are not None)...
After processing overrides, optimization options are:
enabled                : True
opt_level              : O1
cast_model_type        : None
patch_torch_functions  : True
keep_batchnorm_fp32    : None
master_weights         : None
loss_scale             : dynamic

Try manually set _amp_state=0 the to disable this print and did not work
import apex
apex.amp._amp_state = 0


Expected behavior
Give a parameter the set control this print behavior in apex
Environment
CUDA:

GPU:
GeForce RTX 2080 Ti
GeForce RTX 2080 Ti
GeForce RTX 2080 Ti
GeForce RTX 2080 Ti
available: True
version: 10.1
Packages:
numpy: 1.18.1
pyTorch_debug: False
pyTorch_version: 1.4.0
pytorch-lightning: 0.7.5
tensorboard: 2.2.1
tqdm: 4.42.1
System:
OS: Linux
architecture:
64bit

processor: x86_64
python: 3.7.6
version: #38~18.04.1-Ubuntu SMP Tue Mar 31 04:17:56 UTC 2020