Removed unnecessary null check and CompletionStage constant

Author: lutovich

driver/src/main/java/org/neo4j/driver/internal/NetworkSession.java

@@ -46,7 +46,6 @@
 import org.neo4j.driver.v1.exceptions.ClientException;
 import org.neo4j.driver.v1.types.TypeSystem;
 
-import static org.neo4j.driver.internal.util.Futures.completedWithFalse;
 import static org.neo4j.driver.internal.util.Futures.completedWithNull;
 import static org.neo4j.driver.internal.util.Futures.failedFuture;
 import static org.neo4j.driver.v1.Values.value;
@@ -275,10 +274,6 @@ public TypeSystem typeSystem()
 
     CompletionStage<Boolean> currentConnectionIsOpen()
     {
-        if ( connectionStage == null )
-        {
-            return completedWithFalse();
-        }
         return connectionStage.handle( ( connection, error ) ->
                 error == null && // no acquisition error
                 connection != null && // some connection has actually been acquired

driver/src/main/java/org/neo4j/driver/internal/util/Futures.java

@@ -35,7 +35,6 @@
 public final class Futures
 {
     private static final CompletableFuture<?> COMPLETED_WITH_NULL = completedFuture( null );
-    private static final CompletableFuture<Boolean> COMPLETED_WITH_FALSE = completedFuture( false );
 
     private Futures()
     {
@@ -47,11 +46,6 @@ public static <T> CompletableFuture<T> completedWithNull()
         return (CompletableFuture) COMPLETED_WITH_NULL;
     }
 
-    public static CompletableFuture<Boolean> completedWithFalse()
-    {
-        return COMPLETED_WITH_FALSE;
-    }
-
     public static <T> CompletionStage<T> asCompletionStage( io.netty.util.concurrent.Future<T> future )
     {
         CompletableFuture<T> result = new CompletableFuture<>();