Abbreviate SHA-1s when reporting invalid objects

The full 40 digit name is rather long. In most cases an abbreviated
name should be sufficient.

Change-Id: Id16a37c6c745ede1fa0d97c5bc390491799500bc

org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java

@@ -1017,7 +1017,8 @@ public abstract class PackParser {
 				throw new CorruptObjectException(MessageFormat.format(
 						JGitText.get().invalidObject,
 						Constants.typeString(type),
-						id.name(), e.getMessage()), e);
+						readCurs.abbreviate(id, 10).name(),
+						e.getMessage()), e);
 			}
 		}