fix psh hangs at scale

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@529 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-client-2.0/bin/psh

@@ -111,6 +111,7 @@ sub processoutput { #This way, one arbiter handles output, no interrupting
     }
     chomp($line);
     print $nodehdl{$readyh}.": ".$line."\n";
+    IO::Handle::flush(stdout);
   }
   return $rc;
 }