post weeked fixes :-)
change impl. to use READ_NODESREQ to query state of other qmgr(partition)
this as it has no (current) side effects, so that it's possible only to kill
starting cluster (if one started and one starting)
this also impl. gcp safe multi node shutdown
1) block gcp
2) wait for ongoing gcp
3) inform all stopping QMGR's (so that they don't start with error handler)
4) wait for all QMGR's to reply
5) broadcast failrep for stopping nodes
6) (if !master died) unblock gcp
