Use generic file names from commit on a private fork (waiting for inclusion).
* Use most recent ROOT version.
  The ROOT version must always be not smaller than the one used for producing the files,
  in order to avoid forward compatibility issues when deserialising ROOT objects
  (even if the probability is quite low as we are streaming TH* objects).

* Remove root-graf3d from packages required for building: it is anyhow required by root-tree-player.

* For installation, the package now requires a ROOT version not smaller than the one used for building (which should be exactly matching the one in the spec).
  With this change, it is possible to use repo snapshots.
  BEWARE: the usage of this package with newer ROOT versions should be carefully tested!
  In the first tests we made, on a machine running ROOT 5.34.14 and fasthadd built on top of ROOT 5.34.10,
  we observed library misalignment (crash in TBufferFile).