Change megaservice path in line with new file structure (#792)

Signed-off-by: srinarayan-srikanthan <srinarayan.srikanthan@intel.com>

Author: srinarayan-srikanthan

ChatQnA/docker_compose/intel/cpu/xeon/README.md

@@ -126,7 +126,7 @@ cd ..
 
    ```bash
    git clone https://github.com/opea-project/GenAIExamples.git
-   cd GenAIExamples/ChatQnA/docker
+   cd GenAIExamples/ChatQnA
    docker build --no-cache -t opea/chatqna:latest --build-arg https_proxy=$https_proxy --build-arg http_proxy=$http_proxy -f Dockerfile .
    cd ../../..
    ```
@@ -137,7 +137,7 @@ cd ..
 
    ```bash
    git clone https://github.com/opea-project/GenAIExamples.git
-   cd GenAIExamples/ChatQnA/docker
+   cd GenAIExamples/ChatQnA
    docker build --no-cache -t opea/chatqna-without-rerank:latest --build-arg https_proxy=$https_proxy --build-arg http_proxy=$http_proxy -f Dockerfile.without_rerank .
    cd ../../..
    ```