Removed diskInstance attiribute from the common::dataStructures::StorageClass class
Adapted unit tests
Adapted cta-admin commands

StorageClass now belongs to a VO (madatory)
Adapted unit tests
Modified cta-admin command to set the VO of a Storage Class

Deleted Schema version 1.2
Adapted tapepool management so that it works with the new VIRTUAL_ORGANIZATION table
Adapted unit tests so that a VO is created before a tapePool is created
Adapted prepare_test.sh so that it creates a VO before creating the TapePool

Added deletion of existing VOs in the SetUp() method of CatalogueTest

The added codes appeared in production (with the CASTOR Nameserver)
during a network incident with the Oracle Clusterware.

Corrected helgrind errors by adding mutexes for multithread access to RecallReportPacker attributes.

If the disk threads are not finished after the TapeReadSingleThread finished, the status of the drive will be "DrainingToDisk"
This removed a RecallReportPacker exception when trying to release disk space reservation for backpressure

In DriveState::addDiskSpaceReservation and substractDiskSpaceReservation, use a reference to the mutable_disk_space_reservations item

upgrading to eos 4.7.0-20200221155245git994c2f1 that adds eosreports for failed transfers and fix xrootd query prepare on_tape bug

Added UNIQUE constraint on STORAGE_CLASS_NAME and removed the the UNIQUE constraint on DISK_INSTANCE_NAME and STORAGE_CLASS_NAME