MT#7995 lcr_rate: ignore peers without valid fees

Squashed commit of the following:

commit d53dd86b82bcb600c4aeb897bead8b329ccf6e0b
Author: Richard Fuchs <rfuchs@sipwise.com>
Date:   Fri Jul 18 09:30:35 2014 -0400

    fix typo

commit ee645b6b131203d0be8e5d0d92314c6513142f7f
Author: Richard Fuchs <rfuchs@sipwise.com>
Date:   Fri Jul 18 08:28:18 2014 -0400

    segfault fix

commit 2409c1bf286a576797bab2167860daa40ea63fd8
Author: Richard Fuchs <rfuchs@sipwise.com>
Date:   Mon Jul 14 09:58:22 2014 -0400

    MT#8019 lcr_rate: ignore peers without valid fees