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

Change-Id: I7b3fd32f302e93a9903686b627cfc250a69f7e7a
Related: PROD-29251
diff --git a/.kitchen.yml b/.kitchen.yml
index 6e581b6..5875a49 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -18,15 +18,19 @@
     - name: linux
       repo: git
       source: https://gerrit.mcp.mirantis.com/salt-formulas/linux
+      branch: <%=ENV['GERRIT_BRANCH'] || 'master' %>
     - name: apache
       repo: git
       source: https://gerrit.mcp.mirantis.com/salt-formulas/apache
+      branch: <%=ENV['GERRIT_BRANCH'] || 'master' %>
     - name: keystone
       repo: git
       source: https://gerrit.mcp.mirantis.com/salt-formulas/keystone
+      branch: <%=ENV['GERRIT_BRANCH'] || 'master' %>
     - name: oslo_templates
       repo: git
       source: https://gerrit.mcp.mirantis.com/salt-formulas/oslo-templates
+      branch: <%=ENV['GERRIT_BRANCH'] || 'master' %>
   state_top:
     base:
       "*":