Refactor: pacemaker-based: remove unnecessary code

cib_notify_send() called pcmkforeach_ipc_client_remove() unnecessarily, since
there's never a reason to remove a client when sending notifications, and the
function used (cib_notify_send_one()) couldn't possibly return TRUE (to remove
the entry) anyway. So, just use pcmkforeach_ipc_client().

Since that was the only use of pcmk__foreach_ipc_client_remove(), drop that,
too.

Also drop some trace messages that weren't particularly helpful.