EcalCondObjectContainer.h: remove not defined inline function warning

The warning is produced by ROOT6 run-time (Cling/Clang).

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #2112 from davidlt/root6-clean-warnings-EcalCondObjectContainer

EcalCondObjectContainer.h: remove not defined inline function warning