Simplify housekeeper shutdown

The two-part shutdown procedure for the housekeeper was not needed and
caused problems if SIGINT wasn't raised. Since the main thread returns to
the main function, a single shutdown function is all that the housekeeper
needs to function.

Moved all the shutdown related code into Housekeeper::stop to remove the
waiting for the thread in the destructor.

include/maxscale/housekeeper.h

@@ -45,17 +45,7 @@ typedef bool (*TASKFN)(void *data);
 bool hkinit();
 
 /**
- * Shuts down the housekeeper mechanism.
+ * Waits for the housekeeper thread to finish.
- *
- * Should be called @b only if @c hkinit() returned successfully.
- *
- * @see hkinit hkfinish
- */
-void hkshutdown();
-
-/**
- * Waits for the housekeeper thread to finish. Should be called only after
- * hkshutdown() has been called.
  */
 void hkfinish();
 

server/core/gateway.cc

@@ -2336,7 +2336,6 @@ int maxscale_shutdown()
     {
         service_shutdown();
         Worker::shutdown_all();
-        hkshutdown();
         log_flush_shutdown();
     }
 

server/core/housekeeper.cc

@@ -92,7 +92,6 @@ class Housekeeper
 {
 public:
     Housekeeper();
-    ~Housekeeper();
 
     static bool init();
     void stop();
@@ -130,11 +129,6 @@ Housekeeper::Housekeeper():
 {
 }
 
-Housekeeper::~Housekeeper()
-{
-    thread_wait(m_thread);
-}
-
 bool Housekeeper::init()
 {
     struct hkinit_result res;
@@ -190,6 +184,7 @@ void Housekeeper::run()
 void Housekeeper::stop()
 {
     atomic_store_uint32(&m_running, 0);
+    thread_wait(m_thread);
 }
 
 void Housekeeper::add(const Task& task)
@@ -293,18 +288,16 @@ bool hkinit()
     return Housekeeper::init();
 }
 
-void hkshutdown()
-{
-    ss_dassert(hk);
-    hk->stop();
-}
-
 void hkfinish()
 {
+    if (hk)
+    {
         MXS_NOTICE("Waiting for housekeeper to shut down.");
+        hk->stop();
         delete hk;
         hk = NULL;
         MXS_NOTICE("Housekeeper has shut down.");
+    }
 }
 
 void hkshow_tasks(DCB *pDcb)