Move the file for temporary directores to $VARDIR on plab nodes just

like we do for jailed nodes.

tmcd/common/runstartup

@@ -35,7 +35,7 @@ my $logtemplate;
 # Get the config parameters so we can open up a log file in the proper
 # location. See below.
 #
-if (JAILED()) {
+if (JAILED() || PLAB()) {
     $logtemplate = "$VARDIR/logs/runlog.XXXXXX";
 }
 else {