Fix the prereserved feature generation in ptopgen, to add a 0 weight

feature on nodes that are prereserved to the same project as the
experiment, and add a 0.2 weight desire to the vtop file. Rob says it is
okay to always add this desire, so that is what I did.

tbsetup/libvtop_test.pm.in

@@ -2367,6 +2367,9 @@ sub GenVirtNodes($)
 	if (defined($vnode->_startloc())) {
 	    $desires->{"area-" . $vnode->_startloc()} = ['', 1.000000];
 	}
+	# Tell assign to favor nodes that are pre-reserved to the project.
+	$desires->{'prereserved'} = ['', 0.2];
+	
 	# Require that this vnode be placed onto a pnode that supports
 	# the OS it is going to run. However, if the OS is one with a
 	# 'path' (like an OSKit kernel), we don't have an entry in

tbsetup/ptopgen.in

@@ -1156,7 +1156,7 @@ while (($node,$type,$physnode,$class,$issubnode,$def_boot_osid,$reserved,
 	$storage_node{$node} = 1;
     }
 
-    if (defined($prereserved) && !(defined($pid) && $prereserved eq $pid)) {
+    if (defined($prereserved) && (defined($pid) && $prereserved eq $pid)) {
 	$is_prereserved{$node} = $prereserved;
     }
 
@@ -1540,7 +1540,7 @@ foreach $node (@nodenames) {
     }
 
     if (exists($is_prereserved{$node})) {
-	push(@features,"prereserved:0.9");
+	push(@features,"prereserved:0");
     }
 
     # For robots, prefer ones that are already powered on and/or won't need to