Reduce from 8 to 1 TVU receive socket/thread

A single streamer is capable of handling the load, and doing so with a
single thread is more efficient.

gossip/src/cluster_info.rs

@@ -148,7 +148,7 @@ const MIN_NUM_STAKED_NODES: usize = 500;
 // Must have at least one socket to monitor the TVU port
 // The unsafes are safe because we're using fixed, known non-zero values
 pub const MINIMUM_NUM_TVU_SOCKETS: NonZeroUsize = unsafe { NonZeroUsize::new_unchecked(1) };
-pub const DEFAULT_NUM_TVU_SOCKETS: NonZeroUsize = unsafe { NonZeroUsize::new_unchecked(8) };
+pub const DEFAULT_NUM_TVU_SOCKETS: NonZeroUsize = MINIMUM_NUM_TVU_SOCKETS;
 
 #[derive(Debug, PartialEq, Eq, Error)]
 pub enum ClusterInfoError {