Minor updates to windows image files

windows/servercore/10.0.14393/Dockerfile

@@ -1,5 +1,5 @@
-FROM microsoft/windowsservercore:10.0.14393.693
-ENV WINDOWS_IMAGE_VERSION=10.0.14393.693
+FROM microsoft/windowsservercore:10.0.14393.1358
+ENV WINDOWS_IMAGE_VERSION=10.0.14393
 
 RUN mkdir C:\BuildAgent
 WORKDIR C:/BuildAgent

windows/servercore/10.0.14393/standard/VS2017/Dockerfile

@@ -33,14 +33,12 @@ RUN choco install \
     --confirm \
     --limit-output \
     --timeout 216000 \
-    -pre \
     && rmdir /S /Q C:\chococache
 
 RUN choco install \
     visualstudio2017-workload-azure \
     visualstudio2017-workload-netcoretools \
     visualstudio2017-workload-netweb \
-    -pre \
     --confirm \
     --limit-output \
     --timeout 21600 \