Fix exit 1 code on terraform scenario destroy
Fix exit 1 code on terraform scenario destroy

`Makefile` destroy target would always exit 1 due to the use of a
subshell during terraform state file cleanup.

This commit simply allows the subshell to always return true when
deleting the state files.

Signed-off-by: Christopher A. Snapp <dffaa860ed97a8fe2bd7fd9817f16f80af273fae@chef.io>

chef/chef-server,chef/chef-server,chef/chef-server,chef/chef-server,chef/chef-server,chef/chef-server