sdbusplus: replace message::variant with std::variant
sdbusplus: replace message::variant with std::variant

Signed-off-by: Patrick Williams <cbb7353e6d953ef360baf960c122346276c6e320@stwcx.xyz>
Change-Id: I071c28eafe33ac8e2a44010d23a2bd5d8731b540

openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging