Increase time for converting OOoDocument -> PDF -> Image to more reasonable value so we do not get false test failures and still make sure it happens in somehow acceptable time (it's cached after first calculation).

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@38590 20353a03-c40f-0410-a6d1-a30d3c3de9de