Make sure db index is only set once.

See: #2984

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceConnection.java

@@ -961,14 +961,7 @@ public class LettuceConnection extends AbstractRedisConnection {
 
 	@SuppressWarnings("unchecked")
 	protected StatefulConnection<byte[], byte[]> doGetAsyncDedicatedConnection() {
-
-		StatefulConnection<byte[], byte[]> connection = getConnectionProvider().getConnection(StatefulConnection.class);
-
-		if (customizedDatabaseIndex()) {
-			potentiallySelectDatabase(connection, this.dbIndex);
-		}
-
-		return connection;
+		return getConnectionProvider().getConnection(StatefulConnection.class);
 	}
 
 	@Override

src/test/java/org/springframework/data/redis/connection/lettuce/LettuceConnectionUnitTests.java

@@ -25,6 +25,7 @@ import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
 
 import io.lettuce.core.KeyScanCursor;
@@ -188,7 +189,7 @@ class LettuceConnectionUnitTests {
 			connection.getNativeConnection();
 
 			verify(asyncCommandsMock).dispatch(eq(CommandType.SELECT), any(), any());
-			verify(commandsMock).select(1);
+			verifyNoInteractions(commandsMock);
 		}
 
 		@Test // DATAREDIS-603