host-bmc: host_pdr_handler: Drop unused emptyJsonList

```
../host-bmc/host_pdr_handler.cpp:35:25: error: unused variable 'emptyJsonList' [-Werror,-Wunused-const-variable]
   35 | const std::vector<Json> emptyJsonList{};
      |                         ^~~~~~~~~~~~~
```

Change-Id: I25d48daea746ab61caa5c582225ef5ae7ae1c4a3
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/host-bmc/host_pdr_handler.cpp b/host-bmc/host_pdr_handler.cpp
index bbc9816..38d3be9 100644
--- a/host-bmc/host_pdr_handler.cpp
+++ b/host-bmc/host_pdr_handler.cpp
@@ -32,7 +32,6 @@
 using namespace pldm::dbus;
 constexpr auto fruJson = "host_frus.json";
 const Json emptyJson{};
-const std::vector<Json> emptyJsonList{};
 
 template <typename T>
 uint16_t extractTerminusHandle(std::vector<uint8_t>& pdr)