find: gracefully fall back in case of invalid case sensitivity setting
http://bugs.activestate.com/show_bug.cgi?id=98913

(integrated from komodo (trunk) change 80947 by marky)

git-svn-id: https://svn.openkomodo.com/repos/openkomodo/trunk@13264 b87d16e7-d29f-4ee1-b5ec-817d645d335f