Turn on DB retry to avoid transient error.

tbsetup/node_reboot.in

 #!/usr/bin/perl -wT
 #
 # EMULAB-COPYRIGHT
-# Copyright (c) 2000-2004 University of Utah and the Flux Group.
+# Copyright (c) 2000-2005 University of Utah and the Flux Group.
 # All rights reserved.
 #
 use English;
@@ -63,6 +63,9 @@ delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
 # Turn off line buffering on output
 $| = 1;
 
+# Be careful not to exit on transient error
+$libdb::DBQUERY_MAXTRIES = 30;
+
 #
 # We don't want to run this script unless its the real version.
 #