Eliminate verbose output from desimodel_data.sh

[weaverba137]

The script that fetches the extra data associated with desimodel, etc/desimodel_data.sh, is run with #!/bin/bash -x. The extra debugging output may be interpreted by desiInstall as an error message, and prevent normal installation.

[weaverba137]

Additional note. In addition to -x, the script also sets -e, which causes the script to exit on any non-zero return code.

This line:

[[ -z "${DESIMODEL}" ]] && export DESIMODEL=$(pwd)

and specifically [[ -z "${DESIMODEL}" ]] returns 0 during Travis tests, but 1 during desiInstall, because desiInstall has already set $DESIMODEL. In other words, the existence of $DESIMODEL causes the script to fail.