VOL-526 add parameter to support setting the vagrant box name

Change-Id: I6eb7d526a22d3c221f043d7d3e4d5f769b3f84a2
diff --git a/settings.vagrant.nightly.yaml b/settings.vagrant.nightly.yaml
index 10ab061..deb604f 100644
--- a/settings.vagrant.nightly.yaml
+++ b/settings.vagrant.nightly.yaml
@@ -3,6 +3,7 @@
 server_name: "voltha"
 # Use KVM for nightly build
 vProvider: "KVM"
+vagrant_box: "elastic/ubuntu-16.04-x86_64"
 # This determines if test mode is active
 testMode: "false"
 # This determines if installer mode is active