Silences warning.

As I understand it this is not the warning discussed in #78 but it's
good to silence anyways.

examples/wandb_sweeps/train_wandb_sweep.py

@@ -4,13 +4,17 @@
 import argparse
 import functools
 import traceback
+import warnings
 
 import pytorch_lightning as pl
 import wandb
 
 from yoyodyne import train, util
 
 
+warnings.filterwarnings("ignore", ".*is a wandb run already in progress.*")
+
+
 class Error(Exception):
     pass