Remove /etc/user-data

[brikis98]

gruntwork-installer/bootstrap-gruntwork-installer.sh

Line 22 in fe01f10

readonly USER_DATA_DIR="/etc/user-data"

This is legacy code that never got used.

That said, we should standardize on a common install location for all Gruntwork utilities. Perhaps /opt/gruntwork/<repo>/<module>?

[josh-padnick]

I would actually make the path even more explicit:

/opt/gruntwork-utilities/<repo>/<module>.

This way, customers won't think there's some kind of tool called "gruntwork" running on their server.