Bug#39008 perl warning in mtr: 'use of uninitialized value in concatenation' in mtr:3995

mysql-test/mysql-test-run.pl:
  Don't bother to remove particular files from the datadir, based on what 
  config parameters are available. Just remove whole datadir

mysql-test/mysql-test-run.pl

@@ -4015,31 +4015,16 @@ sub start_servers($) {
     }
 
     my $datadir= $mysqld->value('datadir');
-
-    # Don't delete anything if starting dirty
     if (!$opt_start_dirty)
     {
-      my @options= ('log-bin', 'relay-log');
-
-      foreach my $option_name ( @options )  {
-	next unless $mysqld->option($option_name);
-
-	my $value= $mysqld->value($option_name);
+      # Don't delete anything if starting dirty
 
-	foreach my $file ( glob("$datadir/$value*") )
-	{
-	  #print "removing: $file\n";
-	  mtr_debug("Removing '$file'");
-	  unlink($file);
+      if (-d $datadir ) {
+	mtr_verbose(" - removing '$datadir'");
+	rmtree($datadir);
       }
     }
 
-      # Remove old master.info and relay-log.info files
-      # from the servers datadir
-      unlink("$datadir/master.info");
-      unlink("$datadir/relay-log.info");
-    }
-
     # Copy datadir from installed system db
     for my $path ( "$opt_vardir", "$opt_vardir/..") {
       my $install_db= "$path/install.db";