Make sure kitchen test dependencies formulas are always fetched from correct branch

Change-Id: If87c53ede237031508129ec232e4de0129816f7d
Related: PROD-29251
diff --git a/.kitchen.yml b/.kitchen.yml
index eeaf317..1f25671 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -16,6 +16,7 @@
     - name: salt
       repo: git
       source: http://gerrit.mcp.mirantis.com/salt-formulas/salt
+      branch: <%=ENV['GERRIT_BRANCH'] || 'master' %>
   grains:
     noservices: true
   state_top: