Update class name to MDRV2

In this sdbusplus change, [1], the class name in server.hpp was updated
from MDR_V2 to MDRV2. This updates the local class name to match.

[1]: https://github.com/openbmc/sdbusplus/commit/5011340e14da7fc04f8b20721c4631f778200edd

Change-Id: I2c00b29837a72a985b3d1cc359b1bbd952074b63
Signed-off-by: Jason M. Bills <jason.m.bills@intel.com>
3 files changed