fixup some type something about DataObjectHandle payload

before this commit a MergingTransformer could only retrieve a Gaudi::Functional::details::vector_of_const_<NON_CONST_TYPE> and would thus operate with const pointers to non-const objects on the TES. Code copy and pasted from lhcb/LHCb!1914 (comment 2580579).

prerequisite for lhcb/LHCb!1914 (closed)

mentioned in merge request lhcb/LHCb!1914 (closed)

changed milestone to %v33r1

added lhcb-gaudi-head lhcb-lcg-dev4 lhcb-run2-patches-dev4 labels

assigned to @clemenci

• [2020-02-27 00:03] Validation started with lhcb-lcg-dev4#1201
• [2020-02-27 00:04] Validation started with lhcb-gaudi-head#2542
• [2020-02-27 00:10] Validation started with lhcb-run2-patches-dev4#249

approved this merge request

mentioned in commit 182a9d22

merged