Remove unused imports.

Author: tswast

google-cloud-examples/src/main/java/com/google/cloud/examples/bigquery/snippets/BigQuerySnippets.java

@@ -63,9 +63,6 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.ReadableByteChannel;
-import java.nio.channels.WritableByteChannel;
-import java.nio.file.Files;
-import java.nio.file.Path;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;