Relax an out of memory message.

Relax an out of memory message.

The call to ctdb_transport_allocate() can fail for 2 reasons:

* Unable to allocate memory.

* The transport is down, perhaps because CTDB is shutting down.

Either cause will be appropriately logged.

The current use of CTDB_NO_MEMORY_VOID() prints an "out of memory"
message regardless of what happened in ctdb_transport_allocate() and
this could be misleading.

Change this to print a more relaxed message.

Signed-off-by: Martin Schwenke <martin@meltin.net>