Improve output

golang-issue-18555/test.ps1

@@ -1,10 +1,12 @@
 Write-Host Testing new golang image to build on volume mountpoint
 Write-Host The webserver dir before running the go build:
 dir ..\webserver
+Write-Host Building a Go binary inside a container.
 docker run -v "$(pwd)\..\webserver:C:\code" -w /code golang-issue-18555 go build webserver.go
-Write-Host Current dir after running the go build:
 Write-Host The webserver dir after running the go build:
 dir ..\webserver
 if (!(Test-Path ..\webserver\webserver.exe)) {
-  Write-Error "webserver.exe is missing, go build didn't work in container"
+  Write-Error "webserver.exe is missing, go build didn't work in container."
+} else {
+  Write-Host "webserver.exe found, go build works in a container."
 }