Windows-compatibility: Tesseract version number

Some Windows-incompatibilities have crept into the Islandora codebase ([additional background can be found here](https://groups.google.com/d/msg/islandora/0MAhLDjbago/9knbOynlyIcJ "Islandora 7 and Windows: Patches and Tips")).

For some reason, the Windows version of Tesseract identifies itself incorrectly. Despite downloading and installing the "3.02.02" version, running "tesseract -v" gives the incorrect response ("tesseract 3.02"). This hack makes it possible to use OCR under Windows despite this.

*NOTE:* The function *islandora_os_check()* is introduced here: https://github.com/Islandora/islandora/pull/441