locator: topology: Fix move assignment

Defaulted assignment doesn't update node::_topology.

locator/topology.cc

@@ -99,6 +99,14 @@ topology::topology(topology&& o) noexcept
     }
 }
 
+topology& topology::operator=(topology&& o) noexcept {
+    if (this != &o) {
+        this->~topology();
+        new (this) topology(std::move(o));
+    }
+    return *this;
+}
+
 future<topology> topology::clone_gently() const {
     topology ret(_cfg);
     tlogger.debug("topology[{}]: clone_gently to {} from shard {}", fmt::ptr(this), fmt::ptr(&ret), _shard);

locator/topology.hh

@@ -111,11 +111,13 @@ public:
         inet_address this_endpoint;
         endpoint_dc_rack local_dc_rack;
         bool disable_proximity_sorting = false;
+
+        bool operator==(const config&) const = default;
     };
     topology(config cfg);
     topology(topology&&) noexcept;
 
-    topology& operator=(topology&&) = default;
+    topology& operator=(topology&&) noexcept;
 
     future<topology> clone_gently() const;
     future<> clear_gently() noexcept;