Enable cppcoreguidelines-init-variables

We try to enforce this rule, but clearly the robot can do a better job.
Enable the rule, and for init of all variables that clang-tidy finds in
error.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Icf64bc51b3180de29f7e92fa5c5f636e6b1462a6
diff --git a/src/ADCSensorMain.cpp b/src/ADCSensorMain.cpp
index 1fac7dd..fd61680 100644
--- a/src/ADCSensorMain.cpp
+++ b/src/ADCSensorMain.cpp
@@ -108,7 +108,7 @@
                 const std::pair<
                     std::string,
                     boost::container::flat_map<std::string, BasicVariantType>>*
-                    baseConfiguration;
+                    baseConfiguration = nullptr;
                 for (const std::pair<sdbusplus::message::object_path,
                                      SensorData>& sensor : sensorConfigurations)
                 {