Fix: Do not use a hardcoded value for the "DOMAIN_dimensions_ids" attribute.

After the CF-compliance changes, the hardcoded value was sometimes wrong.

git-svn-id: http://forge.ipsl.jussieu.fr/ioserver/svn/XIOS/branchs/xios-1.0@628 d613d254-d18a-4304-b296-5125d4c4d670