-Fix typo in previous chekin

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@5369 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/lib/perl/xCAT/ADUtils.pm

@@ -146,7 +146,7 @@ sub delete_user_account { #provide enough data to construct an /etc/passwd looki
     my $directoryserver = $args{directoryserver};
     my $dnsdomain = $args{dnsdomain};
     my $username = $args{username};
-    unless ($dnsdomain and $directoryserver $username) {
+    unless ($dnsdomain and $directoryserver and $username) {
         die "Invalid arguments";
     }
 }