gossip_load: re-add get_values_all
gossip_load: re-add get_values_all

get_values_all was not reimplemented when moving the value extraction from the
gossip module to the callback module (r7006), but is needed for testing.
tectronics/scalaris,digshock/scalaris,digshock/scalaris,digshock/scalaris,tectronics/scalaris,digshock/scalaris,tectronics/scalaris,tectronics/scalaris,tectronics/scalaris,digshock/scalaris,tectronics/scalaris,seyyed/scalaris,seyyed/scalaris,seyyed/scalaris,digshock/scalaris,digshock/scalaris,seyyed/scalaris,seyyed/scalaris,seyyed/scalaris,seyyed/scalaris,tectronics/scalaris