[easy] Fix logspam on PiecewiseBackend errors (#17138)

Signed-off-by: rzou <[email protected]>

Author: zou3519

vllm/compilation/backends.py

@@ -241,6 +241,8 @@ def __init__(self, module: torch.fx.GraphModule,
         self.graph_pool = graph_pool
         self.vllm_config = vllm_config
         self.vllm_backend = vllm_backend
+        # When True, it annoyingly dumps the torch.fx.Graph on errors.
+        self.extra_traceback = False
 
     def run(self, *args):
         fake_args = [