Enable grub2 support for x86

Author: Obihoernchen

perl-xCAT/xCAT/Utils.pm

@@ -4828,7 +4828,7 @@ sub lookupNetboot {
         $ret = "nimol";
     } elsif ($imgtype =~ /^Linux$/i) {
         if ($osarch =~ /^x86_64$/i) {
-            $ret = "xnba,pxe";
+            $ret = "xnba,pxe,grub2";
         } elsif ($osarch =~ /^ppc64$/i) {
             if (($osv =~ /rh/i and $osn < 7) or ($osv =~ /sles/i and ($osn < 11 or ($osn == 11 and $osm < 4)))) {
                 $ret = "yaboot";