Fix permissions on the swift backup folder

This change sets the permissions expected on the backup folder as it is
currently being set to 640 which is leading to problems with the
swift-ring-builder commands. It should be noted that this folder is not
defined upstream so this is an issue with our fork of the upstream
module.

Change-Id: I4457858694276301dd2315a7ee292b4aa629faaf
Closes-Bug: 1477165

deployment/puppet/swift/manifests/init.pp

@@ -66,6 +66,7 @@ class swift(
   }
   file { '/etc/swift/backups':
     ensure => directory,
+    mode   => '2770',
   }
   file { '/etc/swift/swift.conf':
     ensure => file,