[clang-tidy] use default member init

Found with modernize-use-default-member-init

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/db/Count.cxx

@@ -31,11 +31,11 @@
 #include <map>
 
 struct SearchStats {
-	unsigned n_songs;
+	unsigned n_songs{0};
 	std::chrono::duration<std::uint64_t, SongTime::period> total_duration;
 
 	constexpr SearchStats()
-		:n_songs(0), total_duration(0) {}
+		: total_duration(0) {}
 };
 
 class TagCountMap : public std::map<std::string, SearchStats> {

src/db/plugins/simple/SimpleDatabasePlugin.cxx

@@ -79,8 +79,8 @@ inline SimpleDatabase::SimpleDatabase(AllocatedPath &&_path,
 #ifdef ENABLE_ZLIB
 	 compress(_compress),
 #endif
-	 cache_path(nullptr),
-	 prefixed_light_song(nullptr) {
+	 cache_path(nullptr)
+{
 }
 
 DatabasePtr