Only try to guess where VML is installed if a site.cfg file does exist.
Only try to guess where VML is installed if a site.cfg file does exist.

git-svn-id: 108acfae5aa60014687236af38b4a092d1fda749@72 23631f54-0842-0410-b4f0-d76cd42f001b

erdc-cm/numexpr,erdc-cm/numexpr