convert: Fix detection of LLAMA2

In recent downloads of LLAMA2 dataset the norm_eps is set to 1e-06, this
leads to convert.py erroneously considering the model to be LLAMA1 and
setting the context to 2k tokens.

Fix it by extending the existing hack to also check for the 1e-06 value.

convert.py

@@ -250,7 +250,7 @@ class Params:
         if config.get("rope_theta") == 1000000:
             # CodeLlama
             n_ctx = 16384
-        elif config["norm_eps"] == 1e-05:
+        elif config["norm_eps"] in (1e-05, 1e-06):
             # LLaMA v2
             n_ctx = 4096
         else: