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/FanMain.cpp b/src/FanMain.cpp
index 786498c..a32d054 100644
--- a/src/FanMain.cpp
+++ b/src/FanMain.cpp
@@ -188,7 +188,7 @@
                 // convert to 0 based
                 size_t index = std::stoul(indexStr) - 1;
 
-                const char* baseType;
+                const char* baseType = nullptr;
                 const SensorData* sensorData = nullptr;
                 const std::string* interfacePath = nullptr;
                 const SensorBaseConfiguration* baseConfiguration = nullptr;