Use local salt 2017.7 for offline image build

PROD-35495

Change-Id: Ie93a552fb8e607d7c27f2c331d0d54aac9616209
diff --git a/day01-image/run.example.sh b/day01-image/run.example.sh
index 4ad15c5..c52b2a3 100755
--- a/day01-image/run.example.sh
+++ b/day01-image/run.example.sh
@@ -17,8 +17,8 @@
 export CLUSTER_MODEL_REF="master"
 export CLUSTER_NAME="mcp-day01"
 export MCP_VERSION="proposed"
-export SALTSTACK_REPO="http://mirror.mirantis.com/${MCP_VERSION}/saltstack-2017.7/xenial xenial main"
-export SALTSTACK_GPG="https://repo.saltstack.com/apt/ubuntu/16.04/amd64/2017.7/SALTSTACK-GPG-KEY.pub"
+export SALTSTACK_GPG=${SALTSTACK_GPG:-"http://mirror.mirantis.com/${MCP_VERSION}/saltstack-2017.7/xenial/SALTSTACK-GPG-KEY.pub"}
+export SALTSTACK_REPO=${SALTSTACK_REPO:-"http://mirror.mirantis.com/${MCP_VERSION}/saltstack-2017.7/ xenial main"}
 export APT_MIRANTIS_SALT_REPO="http://mirror.mirantis.com/${MCP_VERSION}/salt-formulas/xenial xenial main"
 export APT_MIRANTIS_SALT_GPG="http://mirror.mirantis.com/${MCP_VERSION}/salt-formulas/xenial/archive-salt-formulas.key"
 export GIT_SALT_FORMULAS_SCRIPTS="https://gerrit.mcp.mirantis.com/salt-formulas/salt-formulas-scripts"