fix condition

Author: ngxson

common/common.cpp

@@ -1618,13 +1618,12 @@ std::string common_get_builtin_chat_template(const struct llama_model * model) {
     static const char * template_key = "tokenizer.chat_template";
     // call with NULL buffer to get the total size of the string
     int32_t res = llama_model_meta_val_str(model, template_key, NULL, 0);
-    if (res < 2) {
-        return "";
-    } else {
+    if (res > 0) {
         std::vector<char> model_template(res + 1, 0);
         llama_model_meta_val_str(model, template_key, model_template.data(), model_template.size());
         return std::string(model_template.data(), model_template.size() - 1);
     }
+    return "";
 }
 
 bool common_chat_verify_template(const std::string & tmpl) {