tools/ctdb: Fix racy ipreallocate code

tools/ctdb: Fix racy ipreallocate code

This code tried to find the recovery master and send an ipreallocate
request to that node.  When a node is stopped, this code asked the
stopped node for recovery master.  Stopped node does not have up-to-date
information on the current recovery master.  So ipreallocate requests
were sent to the wrong node and ignored by that node which is not the
recovery master.

Send ipreallocate request to all active nodes.  That way we guarantee
that the current recovery master will see it and respond to it.

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Pair-Programmed-With: Martin Schwenke <martin@meltin.net>