Add support for django >= 1.4

The python-django package for Ubuntu 14.04 is installing version 1.6.1
whereas the graphite version running on the existing precise servers only
works with django<1.3.  This update conditionally sets the graphite
version to 0.9.15 which requires at least django 1.4.

Change-Id: I348f15ab200b57d3cd9018eb5ba9ebd9e68d56d5

manifests/init.pp

@@ -43,12 +43,18 @@ class graphite(
     ensure => present,
   }
 
+  if $::operatingsystemrelease == '12.04' {
+    # pin version because of https://github.com/graphite-project/graphite-web/issues/650
+    $graphite_rev = '7f8c33da809e2938df55c1ff57ab5329d8d7b878'
+  }
+  else {
+    $graphite_rev = '0.9.x'
+  }
+
   vcsrepo { '/opt/graphite-web':
     ensure   => present,
     provider => git,
-    # revision => '0.9.x',
-    # pin version because of https://github.com/graphite-project/graphite-web/issues/650
-    revision => '7f8c33da809e2938df55c1ff57ab5329d8d7b878',
+    revision => $graphite_rev,
     source   => 'https://github.com/graphite-project/graphite-web.git',
   }