Removes unsupported (deprecated and unused) IPUConfig params from older configs (these will raise an error in latest build of Optimum Graphcore)

ipu_config.json

@@ -18,10 +18,8 @@
   "optimizer_state_offchip": false,
   "optimum_version": "0.1.2",
   "output_mode": "final",
-  "profile_dir": "",
   "recompute_checkpoint_every_layer": true,
   "replicated_tensor_sharding": true,
   "replication_factor": 4,
-  "seed": 42,
-  "use_popdist": false
+  "seed": 42
 }