cluster: ignore extra commas in contact points string

The extra commas provided by the user should be ignored.
In addition, if the user passed an empty contact points string,
the internal contact points should be cleared.

These changes are necessary for ConfigTests to pass.

Author: muzarski

scylla-rust-wrapper/src/cluster.rs

@@ -189,9 +189,10 @@ unsafe fn cluster_set_contact_points(
     let mut contact_points = ptr_to_cstr_n(contact_points_raw, contact_points_length)
         .ok_or(CassError::CASS_ERROR_LIB_BAD_PARAMS)?
         .split(',')
+        .filter(|s| !s.is_empty()) // Extra commas should be ignored.
         .peekable();
 
-    if contact_points.peek().is_none() {
+    if contact_points.peek().is_none() || contact_points.peek().unwrap().is_empty() {
         // If cass_cluster_set_contact_points() is called with empty
         // set of contact points, the contact points should be cleared.
         cluster.contact_points.clear();