New Global Tags for pre2 RelVal.
Test if the Cholesky Matrices are availbale as Event Setup Record; if so, load HcalCholeskyMatricesRcd in HcalDigitizer.
Initialize all pointers in HcalAmplifier.
Protect calls to pointers and, as a workaround, add a fallback to old noise computation when HcalCholeskyMatrices are not set in HcalAmplifier.
Merge pull request #6224 from diguida/autoCond_730pre2

Remove usage of HcalCholeskyMatrix in simulation, and propagate this to the new Global Tags for pre2 RelVal.