Subject: ZK-related issue when updating from 0.94.6 to 0.94.8

Hi there,

I'm trying to upgrade from 0.94.6 (distributed mode) to 0.94.8 and I'm
seeing strange WARN messages leading in region-less regionserver once

Here is the kind of lines I can find:

> WARN org.apache.hadoop.hbase.zookeeper.ZKAssign:
regionserver:60020-0x23d207e751d20c4 Attempt to transition the unassigned
node for 9a
eb2d2c3e878ee50ad4806dd3488c15 from M_ZK_REGION_OFFLINE to
RS_ZK_REGION_OPENING failed, the node existed but was in the state
M_SERVER_SHUTDOWN set by the server,60020,1373289114184

I've uploaded a longer extract including DEBUG traces to Pastebin:

I've performed as usual: stopping the RS, updating HBase binaries and
libraries, then starting the RS... When digging into the log file, I can
read one strange error ZK-related ("ZKW CONSTRUCTOR STACK TRACE FOR
DEBUGGING"), see complete trace here:

Any idea?
Adrien Mogenet