Increment TPCFastSpaceChargeCorrection class version

[shahor02]

To avoid:

root [0] auto mp = o2::gpu::TPCFastTransform::loadFromFile("o2-gpu-TPCFastTransform_1772563162587.root","ccdb_object")
Warning in <TStreamerInfo::BuildCheck>: 
   The StreamerInfo of class o2::gpu::TPCFastSpaceChargeCorrection read from file o2-gpu-TPCFastTransform_1772563162587.root
   has the same version (=4) as the active class but a different checksum.
   You should update the version to ClassDef(o2::gpu::TPCFastSpaceChargeCorrection,5).
   Do not try to write objects with the current class definition,
   the files will not be readable.

Warning in <TStreamerInfo::CompareContent>: The following data member of
the in-memory layout version 4 of class 'o2::gpu::TPCFastSpaceChargeCorrection' is missing from 
the on-file layout version 4:
   unsigned long mCorrectionDataSize; //
Warning in <TStreamerInfo::CompareContent>: The following data member of
the in-memory layout version 4 of class 'o2::gpu::TPCFastSpaceChargeCorrection' is missing from 
the on-file layout version 4:
   int mClassVersion; //
Warning in <TStreamerInfo::CompareContent>: The following data member of
the in-memory layout version 4 of class 'o2::gpu::TPCFastSpaceChargeCorrection' is missing from 
the on-file layout version 4:

[shahor02]

Actually, it appears that the object producing these messages was corrupted. For other objects I don't see this.
I see in the git logs that the TPCFastSpaceChargeCorrection ClassDefNV was incremented from 4 to 5, then decreased back to 4 by @sgorbuno.
I assume it was done on purpose, so closing the PR.