Check powershell version number

Alternative fix for JuliaPackaging#127

Author: simonbyrne

src/PlatformEngines.jl

@@ -260,17 +260,17 @@ function probe_platform_engines!(;verbose::Bool = false)
                 \$webclient.DownloadFile("$url", "$path")
                 """
                 replace(webclient_code, "\n" => " ")
-                return `$psh_path -NoProfile -Command "$webclient_code"`
+                return `$psh_path -Version 3 -NoProfile -Command "$webclient_code"`
             end
         end
 
         # We want to search both the `PATH`, and the direct path for powershell
         psh_path = "C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell"
         prepend!(download_engines, [
-            (`$psh_path -Command ""`, psh_download(psh_path))
+            (`$psh_path  -Version 3 -NoProfile -Command ""`, psh_download(psh_path))
         ])
         prepend!(download_engines, [
-            (`powershell -Command ""`, psh_download(`powershell`))
+            (`powershell -Version 3 -NoProfile -Command ""`, psh_download(`powershell`))
         ])
 
         # We greatly prefer `7z` as a compression engine on Windows
@@ -385,7 +385,11 @@ function probe_platform_engines!(;verbose::Bool = false)
     if !download_found
         errmsg *= "No download engines found. We looked for: "
         errmsg *= join([d[1].exec[1] for d in download_engines], ", ")
-        errmsg *= ". Install one and ensure it  is available on the path.\n"
+        errmsg *= ". Install one and ensure it is available on the path.\n"
+        if Sys.iswindows()
+            errmsg *= "Ensure Windows Management Framework 3.0 or later "
+            errmsg *= "is installed and that Windows PowerShell can be started.\n"
+        end      
     end
 
     if !compression_found