misc: Remove unnecessary metadata lookups (#1448)

Special tokens are already mapped from metadata by llama.cpp

llama_cpp/llama.py

@@ -410,8 +410,8 @@ def __init__(
         if self.verbose:
             print(f"Model metadata: {self.metadata}", file=sys.stderr)
 
-        eos_token_id = int(self.metadata.get("tokenizer.ggml.eos_token_id", self.token_eos()))
-        bos_token_id = int(self.metadata.get("tokenizer.ggml.bos_token_id", self.token_bos()))
+        eos_token_id = self.token_eos()
+        bos_token_id = self.token_bos()
 
         eos_token = self._model.token_get_text(eos_token_id)
         bos_token = self._model.token_get_text(bos_token_id)
@@ -961,9 +961,9 @@ def _create_completion(
 
         completion_id: str = f"cmpl-{str(uuid.uuid4())}"
         created: int = int(time.time())
-        prefix_token_id: int = int(self.metadata.get("tokenizer.ggml.prefix_token_id", self._model.token_prefix()))
-        middle_token_id: int = int(self.metadata.get("tokenizer.ggml.middle_token_id", self._model.token_middle()))
-        suffix_token_id: int = int(self.metadata.get("tokenizer.ggml.suffix_token_id", self._model.token_suffix()))
+        prefix_token_id: int = self._model.token_prefix()
+        middle_token_id: int = self._model.token_middle()
+        suffix_token_id: int = self._model.token_suffix()
         # If prompt is empty, initialize completion with BOS token to avoid
         # detokenization including a space at the beginning of the completion
         completion_tokens: List[int] = [] if len(prompt) > 0 else [self.token_bos()]