scheduler: Use C++11 member initialization, add shutdown assert

"Initializing the members in the declaration makes it easy to spot
uninitialized ones".
https://github.com/bitcoin/bitcoin/blob/master/doc/developer-notes.md#c-data-structures

src/scheduler.cpp

@@ -9,13 +9,14 @@
 #include <assert.h>
 #include <utility>
 
-CScheduler::CScheduler() : nThreadsServicingQueue(0), stopRequested(false), stopWhenEmpty(false)
+CScheduler::CScheduler()
 {
 }
 
 CScheduler::~CScheduler()
 {
     assert(nThreadsServicingQueue == 0);
+    if (stopWhenEmpty) assert(taskQueue.empty());
 }
 
 

src/scheduler.h

@@ -86,9 +86,9 @@ private:
     mutable Mutex newTaskMutex;
     std::condition_variable newTaskScheduled;
     std::multimap<std::chrono::system_clock::time_point, Function> taskQueue GUARDED_BY(newTaskMutex);
-    int nThreadsServicingQueue GUARDED_BY(newTaskMutex);
-    bool stopRequested GUARDED_BY(newTaskMutex);
-    bool stopWhenEmpty GUARDED_BY(newTaskMutex);
+    int nThreadsServicingQueue GUARDED_BY(newTaskMutex){0};
+    bool stopRequested GUARDED_BY(newTaskMutex){false};
+    bool stopWhenEmpty GUARDED_BY(newTaskMutex){false};
     bool shouldStop() const EXCLUSIVE_LOCKS_REQUIRED(newTaskMutex) { return stopRequested || (stopWhenEmpty && taskQueue.empty()); }
 };