gossip_SUITE: set gossip_load interval to zero (reverts r7077)
gossip_SUITE: set gossip_load interval to zero (reverts r7077)

Setting the gossip_load_interval to zero actually does have an effect and makes
the tests faster.
digshock/scalaris,tectronics/scalaris,seyyed/scalaris,seyyed/scalaris,seyyed/scalaris,seyyed/scalaris,seyyed/scalaris,digshock/scalaris,seyyed/scalaris,tectronics/scalaris,digshock/scalaris,tectronics/scalaris,tectronics/scalaris,digshock/scalaris,digshock/scalaris,digshock/scalaris,tectronics/scalaris,tectronics/scalaris,tectronics/scalaris,seyyed/scalaris,digshock/scalaris