Fix iteration over arrays of name-owner watches
Fix iteration over arrays of name-owner watches

Also document why we're iterating backwards.

In tp_dbus_daemon_maybe_free_name_owner_watch, the flawed
reverse-iteration was a bug: we'd skip over the element before a removed
entry, which might mean not freeing it.

In tp_dbus_daemon_cancel_name_owner_watch, it was done correctly (because
there were no deletions), but it did hurt clarity.

Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib