Overwrite existing extracted files if they exist. (#120)

This can only happen if the same archive is being re-extracted after a previous run
has failed midway during extraction.

Author: amr

src/main/java/io/zonky/test/db/postgres/embedded/EmbeddedPostgres.java

@@ -72,7 +72,7 @@
 import org.slf4j.LoggerFactory;
 import org.tukaani.xz.XZInputStream;
 
-import static java.nio.file.StandardOpenOption.CREATE_NEW;
+import static java.nio.file.StandardOpenOption.CREATE;
 import static java.nio.file.StandardOpenOption.WRITE;
 import static java.util.Collections.unmodifiableMap;
 
@@ -706,7 +706,7 @@ private static void extractTxz(InputStream stream, String targetDir) throws IOEx
                     }
                     mkdirs(fsObject.getParentFile());
 
-                    final AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(fsObject.toPath(), CREATE_NEW, WRITE);
+                    final AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(fsObject.toPath(), CREATE, WRITE);
                     final ByteBuffer buffer = ByteBuffer.wrap(content);
 
                     phaser.register();