fix flashattn warning

src/llmtuner/extras/patches/llama_patch.py

@@ -5,11 +5,14 @@ from typing import Optional, Tuple
 from transformers.utils import logging
 from transformers.models.llama.modeling_llama import LlamaAttention, apply_rotary_pos_emb, repeat_kv
 
+is_flash_attn_2_available = False
+
 try:
     from flash_attn import flash_attn_func, flash_attn_varlen_func # type: ignore
     from flash_attn.bert_padding import pad_input, unpad_input # type: ignore
+    is_flash_attn_2_available = True
 except ImportError:
-    print("FlashAttention-2 is not installed, ignore this if you are not using FlashAttention.")
+    is_flash_attn_2_available = False
 
 
 logger = logging.get_logger(__name__)