Revise noderange fix to allow nodels to work again

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@682 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server-2.0/sbin/xcatd

@@ -440,7 +440,7 @@ sub plugin_command {
   my @nodes;
   if ($req->{node}) {
     @nodes = @{$req->{node}};
-  } elsif ($req->{noderange}) {
+  } elsif ($req->{noderange} and $req->{noderange}->[0]) {
     @nodes = noderange($req->{noderange}->[0]);
     if (nodesmissed) {
       my $rsp = {errorcode=>1,error=>"Invalid nodes in noderange:".join(',',nodesmissed)};