[docker-sonic-vs] Create /usr/share/sonic/platform symlink (#5268)

Copying platform.json file into an empty /usr/share/sonic/platform directory does not mimic an actual device. A more correct approach is to create a /usr/share/sonic/platform symlink which links to the actual platform directory; this is more like what is done inside SONiC containers. Then, we only need to copy the platform.json file into the actual platform directory; the symlink takes care of the alternative path, and also exposes all the other files in the platform directory.

platform/vs/docker-sonic-vs/Dockerfile.j2

@@ -136,7 +136,6 @@ COPY ["chassis_db.py", "/usr/bin/"]
 
 COPY ["platform.json", "/usr/share/sonic/device/x86_64-kvm_x86_64-r0/"]
 COPY ["hwsku.json", "/usr/share/sonic/device/x86_64-kvm_x86_64-r0/Force10-S6000/"]
-COPY ["platform.json", "/usr/share/sonic/platform/"]
 
 # Workaround the tcpdump issue
 RUN mv /usr/sbin/tcpdump /usr/bin/tcpdump

platform/vs/docker-sonic-vs/start.sh

@@ -5,6 +5,7 @@
 # NOTE: 'PLATFORM' and 'HWSKU' environment variables are set
 # in the Dockerfile so that they persist for the life of the container
 
+ln -sf /usr/share/sonic/device/$PLATFORM /usr/share/sonic/platform
 ln -sf /usr/share/sonic/device/$PLATFORM/$HWSKU /usr/share/sonic/hwsku
 
 pushd /usr/share/sonic/hwsku