centos7: Don't use Chef's epel enable

The Centos7 AMI already has the epel repo enabled and
something about the Chef receipe to enable the repo
ends up irritating yum (complaining about not being
able to find the data files for the repo).

Signed-off-by: Brian Barrett <[email protected]>

Author: bwbarrett

recipes/base_install.rb

@@ -16,7 +16,9 @@
 case node['platform_family']
 when 'rhel'
   include_recipe 'yum'
-  include_recipe "yum-epel"
+  if node['platform_version'].to_i < 7
+    include_recipe "yum-epel"
+  end
   if node['platform'] == 'redhat'
     execute 'yum-config-manager-rhel' do
       command "yum-config-manager --enable #{node['cfncluster']['rhel']['extra_repo']}"