Update env variable name.
-<!-- Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root. -->
+<!-- Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root. -->
# Create C++ / Java dev environment on CentOS using VirtualBox and Vagrant
##### a. For a dev environment with plain centos/7 and no GUI:
export VESPA_VAGRANT_VM_BOX=centos/7
- export VESPA_DISABLE_VAGRANT_GUI=true
+ export VESPA_VAGRANT_DISABLE_GUI=true
##### b. For a dev environment with GUI and CLion:
