dbus: remove private unused field type_

This commit removes the private unused field type_ from anbox::dbus::Bus
and promotes -Wunused-private-field back to error level on clang.

CMakeLists.txt

@@ -25,7 +25,6 @@ set(EXTRA_C_WARNINGS "-Wcast-align -Wcast-qual -Wformat -Wredundant-decls -Wswit
 set(EXTRA_CXX_WARNINGS "-Wnon-virtual-dtor -Wold-style-cast")
 
 if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-  set(EXTRA_CXX_WARNINGS "${EXTRA_CXX_WARNINGS} -Wno-error=unused-private-field")
   set(EXTRA_CXX_WARNINGS "${EXTRA_CXX_WARNINGS} -Wno-error=unused-const-variable")
   set(EXTRA_CXX_WARNINGS "${EXTRA_CXX_WARNINGS} -Wno-error=unused-lambda-capture")
 endif()

src/anbox/dbus/bus.cpp

@@ -20,9 +20,7 @@
 
 namespace anbox {
 namespace dbus {
-Bus::Bus(Type type) :
-  type_{type} {
-
+Bus::Bus(Type type) {
   int ret = 0;
   switch (type) {
   case Type::Session:

src/anbox/dbus/bus.h

@@ -48,7 +48,6 @@ class Bus : public DoNotCopyOrMove {
  private:
   void worker_main();
 
-  Type type_;
   sd_bus *bus_ = nullptr;
   std::thread worker_thread_;
   std::atomic_bool running_{false};