ctdb-ipalloc: Move if-statement with broken condition

ctdb-ipalloc: Move if-statement with broken condition

This pointer is for an array that is always allocated.  The check is
meant to skip a node that has no IP addresses.  However, when there
are no IP addresses the loop below will not do anything anyway.

Add this as a check at the beginning of the function instead.

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