Prefix openVrInit with m_, like other member objects

src/overlaycontroller.h

@@ -86,7 +86,7 @@ private:
     // OpenVR_Init must be declared before any other class that uses OpenVR
     // function calls since objects are initialized in order of declaration in
     // the class.
-    OpenVR_Init openVrInit;
+    OpenVR_Init m_openVrInit;
 
 public: // I know it's an ugly hack to make them public to enable external
         // access, but I am too lazy to implement getters.