Update SequentialBatchWriter.java

Fix org.apache.accumulo.core.client import statement in SequentialBatchWriter. Replace the '*' catch-all with specified imports.
diff --git a/src/main/java/org/apache/accumulo/examples/client/SequentialBatchWriter.java b/src/main/java/org/apache/accumulo/examples/client/SequentialBatchWriter.java
index 2dd5667..ea8ca2d 100644
--- a/src/main/java/org/apache/accumulo/examples/client/SequentialBatchWriter.java
+++ b/src/main/java/org/apache/accumulo/examples/client/SequentialBatchWriter.java
@@ -18,7 +18,13 @@
 
 import java.util.Random;
 
-import org.apache.accumulo.core.client.*;
+import org.apache.accumulo.core.client.Accumulo;
+import org.apache.accumulo.core.client.AccumuloClient;
+import org.apache.accumulo.core.client.AccumuloException;
+import org.apache.accumulo.core.client.AccumuloSecurityException;
+import org.apache.accumulo.core.client.BatchWriter;
+import org.apache.accumulo.core.client.TableExistsException;
+import org.apache.accumulo.core.client.TableNotFoundException;
 import org.apache.accumulo.core.data.Mutation;
 import org.apache.accumulo.core.data.Value;
 import org.apache.accumulo.examples.cli.ClientOpts;