refs #6603 Moved common getting and/or setting of descriptions and source_file object in both open() and create() calls to common private manager method.  This simplifies the fixes for the current races.
refs #6603 Moved common getting and/or setting of descriptions and source_file object in both open() and create() calls to common private manager method.  This simplifies the fixes for the current races.

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