Enable writing bitmaps during GC by default.

Bitmaps provide a huge performance boost for counting objects and they
play nice with the cgit implementation.

Change-Id: I33b05a6c8f1ee2df7770f0b9fdc50d0b4bbf1029

org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackConfig.java

@@ -135,7 +135,7 @@ public class PackConfig {
 	 *
 	 * @see #setBuildBitmaps(boolean)
 	 */
-	public static final boolean DEFAULT_BUILD_BITMAPS = false;
+	public static final boolean DEFAULT_BUILD_BITMAPS = true;
 
 
 	private int compressionLevel = Deflater.DEFAULT_COMPRESSION;