TIFF: attempt to correct incorrectly stored StripByteCounts values

If an entry in the StripByteCounts array is negative, this logs the
original value and attempts to set it to the previous entry in the
array.

Fixes http://trac.openmicroscopy.org.uk/ome/ticket/12583.

To test, verify that the file from QA 9563 throws an exception as referenced in the ticket without this change.  With this change, the same file should open/import without throwing an exception, and the image should look "reasonable" - ImageMagick gives similar results, but leaves the last strip empty instead of correcting the byte count and reading the stored pixel values.

Builds should remain green, as I would not expect this to affect other files in the repository.