[CrashFix]修正地图清标记是引发的空指针

libraries/mogo-map/src/main/java/com/mogo/map/marker/AMapMarkerWrapper.java

@@ -77,11 +77,13 @@ public class AMapMarkerWrapper implements IMogoMarker, Observer {
             mMogoMarkerOptions.deleteObservers();
             mMogoMarkerOptions = null;
         }
-        if ( mMarker != null ) {
-            mMarker.remove();
-            mMarker.setMObject( null );
-            mMarker.setOnInfoWindowClickListener( null );
-            mMarker = null;
+        synchronized (this) {
+            if ( mMarker != null ) {
+                mMarker.remove();
+                mMarker.setMObject( null );
+                mMarker.setOnInfoWindowClickListener( null );
+                mMarker = null;
+            }
         }
         mMogoInfoWindowAdapter = null;
         mMogoMarkerClickListener = null;