Enable init checker

clang-tidy added cppcoreguidelines-init-variables as a check, which is
something we already enforce to some extent, but getting CI to enforce
it will help reviews move faster.

Tested: Code compiles.  Noop changes.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I7e10950de617b1d3262265572b1703f2e60b69d0
diff --git a/include/openbmc_dbus_rest.hpp b/include/openbmc_dbus_rest.hpp
index 7f16ea8..0b54c65 100644
--- a/include/openbmc_dbus_rest.hpp
+++ b/include/openbmc_dbus_rest.hpp
@@ -1104,7 +1104,7 @@
 inline int readVariantFromMessage(sdbusplus::message::message& m,
                                   nlohmann::json& data)
 {
-    const char* containerType;
+    const char* containerType = nullptr;
     int r = sd_bus_message_peek_type(m.get(), nullptr, &containerType);
     if (r < 0)
     {