Shutdown fixes

- tell sql thread to finish only after the other threads finished
- prevents other threads stalling on sql replies

src/shutdown.py

@@ -35,22 +35,24 @@ def doCleanShutdown():
     while state.shutdown == 1:
         time.sleep(.1)
     
+    # Wait long enough to guarantee that any running proof of work worker threads will check the
+    # shutdown variable and exit. If the main thread closes before they do then they won't stop.
+    time.sleep(.25)
+
+    for thread in threading.enumerate():
+        if (thread is not threading.currentThread() and
+            isinstance(thread, StoppableThread) and
+            thread.name != 'SQL'):
+            logger.debug("Waiting for thread %s", thread.name)
+            thread.join()
+
     # This one last useless query will guarantee that the previous flush committed and that the
     # objectProcessorThread committed before we close the program.
     sqlQuery('SELECT address FROM subscriptions')
     logger.info('Finished flushing inventory.')
     sqlStoredProcedure('exit')
 
-    # Wait long enough to guarantee that any running proof of work worker threads will check the
-    # shutdown variable and exit. If the main thread closes before they do then they won't stop.
-    time.sleep(.25)
-
-    for thread in threading.enumerate():
-        if thread is not threading.currentThread() and isinstance(thread, StoppableThread):
-            logger.debug("Waiting for thread %s", thread.name)
-            thread.join()
-
-    # flush queued
+    # flush queues
     for queue in (workerQueue, UISignalQueue, addressGeneratorQueue, objectProcessorQueue):
         while True:
             try: