Fixed prepare.sh and other small fixes

List of fixes:
- Use -g option to set ext gw info for heat-router in prepare.sh
- Fixed -H option in prepare.sh
- Fixed default working directory in prepare.sh
- Use admin_username from env vars in prepare.sh
- Set additional quotas for cvp.project
- Use mirantis busybox image from mirantis registry
- Fixed FIXED_NET variable in rally templates

Related-PROD: PROD-37187
Change-Id: I3d3ea6a520cf1677aabfa356bc40c19ae04822b4
diff --git a/k8s/rally-files/openstack-mos-scn-i1-static-users.json b/k8s/rally-files/openstack-mos-scn-i1-static-users.json
index 23748c1..200bcd8 100644
--- a/k8s/rally-files/openstack-mos-scn-i1-static-users.json
+++ b/k8s/rally-files/openstack-mos-scn-i1-static-users.json
@@ -8,7 +8,7 @@
 {% set tenants = 1 %}
 {% set rbd_image = "https://download.cirros-cloud.net/0.6.2/cirros-0.6.2-x86_64-disk.img" %}
 {% set heat_template = "/rally/rally-files/default.yaml.template" %}
-{% set fixed_net = "id" %}
+{% set fixed_net = "${FIXED_NET}" %}
 
 {
   "KeystoneBasic.authenticate_user_and_validate_token": [