recoverd: Clean up log messages in remote IP verification

recoverd: Clean up log messages in remote IP verification

The log messages in verify_remote_ip_allocation() are confusing
because they don't include the PNN of the problem node, because it is
not known in this function.

Add the PNN of the node being verified as a function argument and then
shuffle the log messages around to make them clearer.

Also fold 3 nested if statements into just one.

Signed-off-by: Martin Schwenke <martin@meltin.net>
(This used to be ctdb commit f0942fa01cd422133fc9398f56b4855397d7bc86)