Fix a mistake in build.sh

The build is currently out of sync with rfluka_patch.  This will fix it.

This pull request is being done in the svalinn repo because julry/DAGMC-CI will not allow a pull request to svalinn/DAGMC-CI.  Possibly julry/DAGMC-CI is not a proper fork of svalinn/DAGMC-CI.  After this pull I am deleting julry/DAGMC-CI and creating a fork on julry.  In future pull requests by me will come from there.