update ingres html description pages : The old version of this page is way out of date and did not reflect the current state of Ingres.  I also included instructions for enabling support for old ingres types. (by Tyler Mitchell, pull request #15)

git-svn-id: https://svn.osgeo.org/gdal/trunk@26040 f0d54148-0727-0410-94bb-9a71ac55c965