-Guard against makehosts matching blank lines when or is messed up

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@2761 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/lib/xcat/plugins/hosts.pm

@@ -22,6 +22,7 @@ sub handled_commands {
 sub addnode {
   my $node = shift;
   my $ip = shift;
+  unless ($node and $ip) { return; } #bail if requested to do something that could zap /etc/hosts badly
   my $othernames = shift;
   my $idx=0;
   my $foundone=0;