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

Change-Id: I340390546daff305dc0254ffc5605fa23761a865
Related: PROD-29251
diff --git a/.kitchen.yml b/.kitchen.yml
index 693979d..14554fc 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -18,9 +18,11 @@
     - name: linux
       repo: git
       source: https://gerrit.mcp.mirantis.com/salt-formulas/linux.git
+      branch: <%=ENV['GERRIT_BRANCH'] || 'master' %>
     - name: salt
       repo: git
       source: https://gerrit.mcp.mirantis.com/salt-formulas/salt.git
+      branch: <%=ENV['GERRIT_BRANCH'] || 'master' %>
   state_top:
     base:
       "*":