storage_util: Prefer generic FICLONE over btrfs/xfs defines
storage_util: Prefer generic FICLONE over btrfs/xfs defines

After my change to the original patch that resulted in commit
8ed874b39b3 it was brought to my attention that all three defines
are the same: FICLONE = BTRFS_IOC_CLONE = XFS_IOC_CLONE (as
documented in ioctl_ficlone(2)). Therefore we should prefer
generic FICLONE over 'specific' defines for btrfs/xfs.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>

libvirt/libvirt,andreabolognani/libvirt,eskultety/libvirt,eskultety/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,crobinso/libvirt,olafhering/libvirt,fabianfreyer/libvirt,libvirt/libvirt,zippy2/libvirt,nertpinx/libvirt,zippy2/libvirt,eskultety/libvirt,nertpinx/libvirt,jfehlig/libvirt,libvirt/libvirt,jfehlig/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,crobinso/libvirt,andreabolognani/libvirt,jardasgit/libvirt,jardasgit/libvirt,andreabolognani/libvirt,zippy2/libvirt,andreabolognani/libvirt,crobinso/libvirt,crobinso/libvirt,jardasgit/libvirt,nertpinx/libvirt,zippy2/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,nertpinx/libvirt,jardasgit/libvirt,olafhering/libvirt,jardasgit/libvirt,olafhering/libvirt,eskultety/libvirt,olafhering/libvirt,fabianfreyer/libvirt,eskultety/libvirt,jfehlig/libvirt