Fixing signals.

Taking the signal handles later, so during loads,
regular signal handling is done, we only need to handle SIGINT and
SIGTERM during real loads to get more graceful shutdowns when queries
are in flight.

server/text_generation_server/server.py

@@ -35,9 +35,6 @@ class SignalHandler:
         self.KEEP_PROCESSING = False
 
 
-signal_handler = SignalHandler()
-
-
 class TextGenerationService(generate_pb2_grpc.TextGenerationServiceServicer):
     def __init__(
         self,
@@ -251,7 +248,7 @@ def serve(
         await server.start()
 
         logger.info("Server started at {}".format(local_url))
-
+        signal_handler = SignalHandler()
         while signal_handler.KEEP_PROCESSING:
             await asyncio.sleep(0.5)