better atomic flagging for story session resets by sync service

clients/android/NewsBlur/src/com/newsblur/fragment/ItemListFragment.java

@@ -69,6 +69,8 @@ public abstract class ItemListFragment extends NbFragment implements OnScrollLis
 		super.onCreate(savedInstanceState);
         defaultFeedView = (DefaultFeedView)getArguments().getSerializable("defaultFeedView");
         activity = (ItemsList) getActivity();
+        // tell the sync service to discard the reading session at the start of the next sync, just in case
+        NBSyncService.resetReadingSession();
     }
 
 	@Override

clients/android/NewsBlur/src/com/newsblur/service/NBSyncService.java

@@ -633,17 +633,21 @@ public class NBSyncService extends Service {
             StoryOrder order = PrefsUtils.getStoryOrder(this, fs);
             ReadFilter filter = PrefsUtils.getReadFilter(this, fs);
 
+            boolean doReset = false;
             synchronized (PENDING_FEED_MUTEX) {
                 if (ResetSession) {
-                    // the next fetch will be the start of a new reading session; clear it so it
+                    doReset = true;
-                    // will be re-primed
-                    dbHelper.clearStorySession();
-                    // don't just rely on the auto-prepare code when fetching stories, it might be called
-                    // after we insert our first page and not trigger
-                    dbHelper.prepareReadingSession(fs);
                     ResetSession = false;
                 }
             }
+            if (doReset) {
+                // the next fetch will be the start of a new reading session; clear it so it
+                // will be re-primed
+                dbHelper.clearStorySession();
+                // don't just rely on the auto-prepare code when fetching stories, it might be called
+                // after we insert our first page and not trigger
+                dbHelper.prepareReadingSession(fs);
+            }
             
             while (totalStoriesSeen < PendingFeedTarget) {
                 if (stopSync()) return;