virConnectCloseCallbackData: fix connection object refcount

We have reference to connection object in virConnectCloseCallbackData
object thus we have to refcount it. Obviously we have problems
in dispose and call functions. Let's fix it.
Signed-off-by: NNikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>

src/datatypes.c

@@ -180,6 +180,7 @@ virConnectCloseCallbackDataDispose(void *obj)
 
     if (cb->freeCallback)
         cb->freeCallback(cb->opaque);
+    virObjectUnref(cb->conn);
 
     virObjectUnlock(cb);
 }
@@ -226,6 +227,7 @@ void virConnectCloseCallbackDataUnregister(virConnectCloseCallbackDataPtr close,
         close->freeCallback(close->opaque);
     close->freeCallback = NULL;
     virObjectUnref(close->conn);
+    close->conn = NULL;
 
  cleanup:
 
@@ -248,6 +250,8 @@ void virConnectCloseCallbackDataCall(virConnectCloseCallbackDataPtr close,
         close->freeCallback(close->opaque);
     close->callback = NULL;
     close->freeCallback = NULL;
+    virObjectUnref(close->conn);
+    close->conn = NULL;
 
  exit:
     virObjectUnlock(close);