[RUBY-125] avoid deadlocks during cleanup on connection fail

Author: Bulat Shakirzyanov

lib/cassandra/cluster/control_connection.rb

@@ -60,9 +60,6 @@ def connect_async
           plan = @load_balancing_policy.plan(nil, VOID_STATEMENT, VOID_OPTIONS)
           connect_to_first_available(plan)
         end
-        f.on_failure do |e|
-          close_async
-        end
         f
       end
 

lib/cassandra/driver.rb

@@ -148,9 +148,8 @@ def connect(addresses)
           promise.fulfill(cluster)
         else
           f.on_failure do |e|
-            cluster.close_async.on_complete do |_, _|
-              promise.break(e)
-            end
+            cluster.close_async
+            promise.break(e)
           end
         end
       end