(GH-827) No really, ignore package exit codes

If it is a valid exit code, choco used to set the exit code to zero.
Otherwise the exit code was set to 1. That behavior needs to continue to
be that way for the exit code of choco.exe when ignoring package exit
codes.

src/chocolatey/infrastructure.app/services/PowershellService.cs

@@ -301,6 +301,11 @@ public bool run_action(ChocolateyConfiguration configuration, PackageResult pack
                         failure = true;
                     }
 
+                    if (!configuration.Features.UsePackageExitCodes)
+                    {
+                        Environment.ExitCode = failure ? 1 : 0;
+                    }
+
                     if (failure)
                     {
                         packageResult.Messages.Add(new ResultMessage(ResultType.Error, "Error while running '{0}'.{1} See log for details.".format_with(chocoPowerShellScript, Environment.NewLine)));