fixup argument passing

lib/lindev_users.ps1

@@ -27,8 +27,15 @@ if (-not $nocred){
 }
 
 get-adgroupmember @psargs | % {
-	$asdf=$_
-	get-aduser -Identity $_ -Server $wtserver -Properties uidnumber,gidnumber,mail,enabled -Credential $global:wtcred
+	$groupmemargs = @{
+		Identity=$_
+		Server=$wtserver
+		Properties=@("uidnumber","gidnumber","mail","enabled")
+	}
+	if ($null -ne $global:wtcred){
+		$groupmemargs.Credential=$global:wtcred
+	}
+	get-aduser @groupmemargs
 } |
 	select UserPrincipalName,uidnumber,gidnumber,mail,enabled | 
 	sort uidnumber |