Performed the reproduction steps and found no issues. Additionally, kept the renaming process in the parallel, added and removed bricks and started rebalance. No NULL messages in the logs. Marking the bug verified...!
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2015-0095.html
*** Bug 1155172 has been marked as a duplicate of this bug. ***