Implemented OStoreDB::RetrieveMount::getNextJob()

objectstore/ArchiveToFileRequest.hpp

objectstore/RetrieveToFileRequest.cpp

objectstore/RetrieveToFileRequest.hpp

objectstore/Tape.cpp

objectstore/Tape.hpp

scheduler/ArchiveMount.cpp

scheduler/OStoreDB/OStoreDB.cpp

scheduler/OStoreDB/OStoreDB.hpp

scheduler/RetrieveJob.cpp

scheduler/RetrieveJob.hpp

scheduler/RetrieveMount.cpp

scheduler/RetrieveMount.hpp

scheduler/Scheduler.cpp

scheduler/SchedulerDatabase.hpp

...castor/tape/tapeserver/daemon/DataTransferSessionTest.cpp

tapeserver/castor/tape/tapeserver/daemon/DiskWriteTask.cpp

...erver/castor/tape/tapeserver/daemon/DiskWriteTaskTest.cpp

...castor/tape/tapeserver/daemon/DiskWriteThreadPoolTest.cpp

.../castor/tape/tapeserver/daemon/RecallReportPackerTest.cpp

...rver/castor/tape/tapeserver/daemon/RecallTaskInjector.cpp