Fix illegal variable name for pythonpath in web module

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,
 ) {
 
   include sitescripts
 
-  $PYTHONPATH = 'PYTHONPATH=/opt/cms:/opt/sitescripts'
+  $pythonpath = 'PYTHONPATH=/opt/cms:/opt/sitescripts'
 
   # Ensure there is at least one character in the respective strings;
   # see https://codereview.adblockplus.org/29329028/#msg3
   validate_re($vhost, '.+')
   validate_re($repository, '.+')
 
   File {
     owner  => 'root',
     group  => 'root',
     mode   => 0644,
   }
 
   Cron {
     environment => concat(hiera('cron::environment', []), [
-      $PYTHONPATH,
+      $pythonpath,
     ]),
   }
 
   class {'nginx':
     geoip_country => $geoip ? {
       false => undef,
       default => '/usr/share/GeoIP/GeoIPv6.dat',
     },
   }
 
@@ skipping 93 matching lines @@
   $initialize_content_exec = [
     'python', '-m', 'cms.bin.generate_static_pages',
     "/home/www/${repository}", "/var/www/${vhost}",
   ]
 
   exec {"initialize_content":
     command => shellquote($initialize_content_exec),
     user => www,
     subscribe => [Exec["fetch_repo"], Exec["fetch_cms"]],
     refreshonly => true,
-    environment => $PYTHONPATH,
+    environment => $pythonpath,
   }
 
   file {'/var/www':
     ensure => directory,
     mode => 755,
   }
 
   file {[
     "/var/cache/$repository",
     "/var/www/$vhost",
@@ skipping 32 matching lines @@
   )
 
   cron {'update_repo':
     ensure => present,
     command => $update_webpage_cmd,
     user => www,
     minute  => '5-59/20',
   }
 
 }