Fix for superfluous "Accepting..." warnings from RC during live sync

The fix addresses #197 (closed)

After a bit of struggle with external test, I've finally decided the trouble is not worth it and made a unit test. The problematic situation was emulated by popping and reapplying block on single node (making multiple nodes is easy with test_tools, but controlling RC and log is harder; on the other hand making multiple nodes in unit tests can only be emulated because hived application is a singleton).