Don't crash if XGLMSinusoidalPositionalEmbedding doesn't exist

aiserver.py

@@ -768,7 +768,11 @@ if(not vars.model in ["InferKit", "Colab", "OAI", "ReadOnly", "TPUMeshTransforme
         # Temporary fix for XGLM positional embedding issues until
         # https://github.com/huggingface/transformers/issues/15736
         # is resolved
+        try:
             from transformers.models.xglm.modeling_xglm import XGLMSinusoidalPositionalEmbedding
+        except ImportError:
+            pass
+        else:
             @torch.no_grad()
             def new_forward(self, input_ids: torch.Tensor = None, inputs_embeds: torch.Tensor = None, past_key_values_length: int = 0):
                 bsz, seq_len = inputs_embeds.size()[:-1]