talk-llama : correct default speak.sh path (#720)

There is `speak.sh` file in `./examples/talk-llama` as described in README.
However `./examples/talk/speak.sh` is used in `talk-llama.cpp`, this commit corrects that.

examples/talk-llama/talk-llama.cpp

@@ -49,7 +49,7 @@ struct whisper_params {
     std::string language    = "en";
     std::string model_wsp   = "models/ggml-base.en.bin";
     std::string model_llama = "models/ggml-llama-7B.bin";
-    std::string speak       = "./examples/talk/speak.sh";
+    std::string speak       = "./examples/talk-llama/speak.sh";
     std::string prompt      = "";
     std::string fname_out;
 };