Even if there is no source file in the m_table, the unlink must happen in the backup.  Also some error handling was not quite right.
Even if there is no source file in the m_table, the unlink must happen in the backup.  Also some error handling was not quite right.

dbpercona/Percona-TokuBackup,percona/Percona-TokuBackup,dbpercona/Percona-TokuBackup,tplavcic/Percona-TokuBackup,Jun-Yuan/Percona-TokuBackup,Jun-Yuan/Percona-TokuBackup,kbauskar/Percona-TokuBackup,guiquanz/Percona-TokuBackup,guiquanz/Percona-TokuBackup,Jun-Yuan/Percona-TokuBackup,kbauskar/Percona-TokuBackup,dbpercona/Percona-TokuBackup,guiquanz/Percona-TokuBackup,tplavcic/Percona-TokuBackup,percona/Percona-TokuBackup,percona/Percona-TokuBackup,tplavcic/Percona-TokuBackup,Jun-Yuan/Percona-TokuBackup,guiquanz/Percona-TokuBackup,percona/Percona-TokuBackup,tplavcic/Percona-TokuBackup,kbauskar/Percona-TokuBackup,dbpercona/Percona-TokuBackup,kbauskar/Percona-TokuBackup