State.Chassis: update service name

Both phosphor-state-manager and x86-power-control have code that exposes
both the Chassis and Chassis0 bus names as a backwards compatibility
when multi-chassis support was added.  Switch to the numbered bus name,
which is expected to be the non-deprecated one.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ic20cddf51ced0a47fa8b754ec6bda6be5781412e
diff --git a/src/host_then_chassis_poweroff.cpp b/src/host_then_chassis_poweroff.cpp
index 0178983..5aedc9f 100644
--- a/src/host_then_chassis_poweroff.cpp
+++ b/src/host_then_chassis_poweroff.cpp
@@ -17,7 +17,7 @@
 namespace service
 {
 constexpr auto bmcState = "xyz.openbmc_project.State.BMC";
-constexpr auto chassisState = "xyz.openbmc_project.State.Chassis";
+constexpr auto chassisState = "xyz.openbmc_project.State.Chassis0";
 constexpr auto hostState = "xyz.openbmc_project.State.Host";
 } // namespace service