Use -NoProfile in powershell to (hopefully) suppress output

Author: ianfixes

lib/arduino_ci/arduino_downloader_windows.rb

@@ -10,8 +10,8 @@ module ArduinoCI
   class ArduinoDownloaderWindows < ArduinoDownloader
 
     def powershell(*args)
-      encoded_cmd = Base64.strict_encode64((args.shelljoin + " | Out-Null").encode('utf-16le'))
-      system("powershell.exe", "-encodedCommand", encoded_cmd)
+      encoded_cmd = Base64.strict_encode64(args.shelljoin.encode('utf-16le'))
+      system("powershell.exe", "-NoProfile", "-encodedCommand", encoded_cmd)
     end
 
     def cygwin(*args)