Remove final metrics reference

This changeset removes a leftover reference to the gds_metrics library, which was taken out previously.

Signed-off-by: Carlo Costino <carlo.costino@gsa.gov>

gunicorn_config.py

@@ -5,7 +5,6 @@ import traceback
 
 import eventlet
 import gunicorn
-from gds_metrics.gunicorn import child_exit  # noqa
 
 workers = 5
 worker_class = "eventlet"