Update opscode yum cookbook

Encountered the following issue:

```
gems.service.verticloud.com: [2013-08-08T04:19:18+00:00] INFO: Processing remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm] action create (yum::epel line 33)
gems.service.verticloud.com: [2013-08-08T04:19:19+00:00] INFO: Retrying execution of remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm], 4 attempt(s) left
gems.service.verticloud.com: [2013-08-08T04:19:23+00:00] INFO: Retrying execution of remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm], 3 attempt(s) left
gems.service.verticloud.com: [2013-08-08T04:19:26+00:00] INFO: Retrying execution of remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm], 2 attempt(s) left
gems.service.verticloud.com: [2013-08-08T04:19:29+00:00] INFO: Retrying execution of remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm], 1 attempt(s) left
gems.service.verticloud.com: [2013-08-08T04:19:33+00:00] INFO: Retrying execution of remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm], 0 attempt(s) left
gems.service.verticloud.com: 
gems.service.verticloud.com: ================================================================================
gems.service.verticloud.com: Error executing action `create` on resource 'remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm]'
gems.service.verticloud.com: ================================================================================
gems.service.verticloud.com: 
gems.service.verticloud.com: Net::HTTPServerException
gems.service.verticloud.com: ------------------------
gems.service.verticloud.com: 403 "Forbidden"
gems.service.verticloud.com: 
gems.service.verticloud.com: Resource Declaration:
gems.service.verticloud.com: ---------------------
gems.service.verticloud.com: # In /tmp/exec/cookbooks/yum/recipes/epel.rb
gems.service.verticloud.com: 
gems.service.verticloud.com:  33:   remote_file "#{Chef::Config[:file_cache_path]}/epel-release-#{epel}.noarch.rpm" do
gems.service.verticloud.com:  34:     source "http://download.fedoraproject.org/pub/epel/#{major}/i386/epel-release-#{epel}.noarch.rpm"
gems.service.verticloud.com:  35:     not_if "rpm -qa | egrep -qx 'epel-release-#{epel}(|.noarch)'"
gems.service.verticloud.com:  36:     notifies :install, "rpm_package[epel-release]", :immediately
gems.service.verticloud.com:  37:     retries 5 # We may be redirected to a FTP URL, CHEF-1031.
gems.service.verticloud.com:  38:   end
gems.service.verticloud.com:  39: 
gems.service.verticloud.com: 
gems.service.verticloud.com: Compiled Resource:
gems.service.verticloud.com: ------------------
gems.service.verticloud.com: # Declared in /tmp/exec/cookbooks/yum/recipes/epel.rb:33:in `from_file'
gems.service.verticloud.com: 
gems.service.verticloud.com: remote_file("/var/chef/cache/epel-release-6-7.noarch.rpm") do
gems.service.verticloud.com:   provider Chef::Provider::RemoteFile
gems.service.verticloud.com:   action "create"
gems.service.verticloud.com:   retries 0
gems.service.verticloud.com:   retry_delay 2
gems.service.verticloud.com:   path "/var/chef/cache/epel-release-6-7.noarch.rpm"
gems.service.verticloud.com:   backup 5
gems.service.verticloud.com:   source "http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-7.noarch.rpm"
gems.service.verticloud.com:   cookbook_name :yum
gems.service.verticloud.com:   recipe_name "epel"
gems.service.verticloud.com:   not_if "rpm -qa | egrep -qx 'epel-release-6-7(|.noarch)'"
gems.service.verticloud.com: end
gems.service.verticloud.com: 
gems.service.verticloud.com: [2013-08-08T04:19:36+00:00] ERROR: Running exception handlers
gems.service.verticloud.com: [2013-08-08T04:19:36+00:00] ERROR: Exception handlers complete
gems.service.verticloud.com: [2013-08-08T04:19:36+00:00] FATAL: Stacktrace dumped to /var/chef/cache/chef-stacktrace.out
gems.service.verticloud.com: [2013-08-08T04:19:36+00:00] FATAL: Net::HTTPServerException: remote_file[/var/chef/cache/epel-release-6-7.noarch.rpm] (yum::epel line 33) had an error: Net::HTTPServerException: 403 "Forbidden"

```