Issue 3996 - Make sure to install current versions of Markdown and Jinja2 modules on web servers

modules/web/manifests/server.pp

 class web::server(
     $vhost,
     $repository,
     $certificate = hiera('web::server::certificate', 'undef'),
     $private_key = hiera('web::server::private_key', 'undef'),
     $is_default = false,
     $aliases = undef,
     $custom_config = undef,
     $multiplexer_locations = undef,
     $geoip = false,
@@ skipping 26 matching lines @@
   }
 
   class {'geoip':
     cron => {hour => 0, minute => 8, monthday => 15},
     ensure => $geoip ? {false => 'absent', default => 'present'},
   }
 
   ensure_packages(['python-pip'])
 
   # Make sure that apt packages corresponding to the pip-installed modules below
-  # aren't present, these will take precedence otherwise.
+  # won't be installed unintentionally, these will take precedence otherwise.
   package {['python-jinja2', 'python-markdown']:
-    ensure => purged
+    ensure => 'held',
   }
 
   package {'Jinja2':
     ensure => '2.8',
     provider => 'pip',
     require => [Package['python-pip'], Package['python-jinja2']],
   }
 
   package {'markdown':
     ensure => '2.6.6',
@@ skipping 115 matching lines @@
       Class['sitescripts'],
       Exec['install_jsdoc'],
       Package['make', 'doxygen'],
       File['/var/www/docs'],
     ],
     command => 'python -m sitescripts.docs.bin.generate_docs',
     user => www,
     minute => '5-55/10',
   }
 }