ext3: Fix set but unused variables

[tytso@mit.edu: Fix compilation with CONFIG_JBD_DEBUG enabled]

Acked-by:  <tytso@mit.edu>
cc: linux-ext4@vger.kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>