Fix compilation with ROOT 6.20
With the fix to https://sft.its.cern.ch/jira/browse/ROOT-10512 that will be in ROOT 6.20/00, the changes introduced with !1682 (merged) fail to compile.
This fixes the problem.
With the fix to https://sft.its.cern.ch/jira/browse/ROOT-10512 that will be in ROOT 6.20/00, the changes introduced with !1682 (merged) fail to compile.
This fixes the problem.