Use distro packages for nginx

The packages provided by the nginx developers causes dependency issues
with epel enabled.

manifests/system.pp

@@ -146,7 +146,9 @@ class analysator::system::pxe_install {
     mode   => '0444',
   }
 
-  include ::nginx
+  class { '::nginx':
+    manage_repo => false,
+  }
   nginx::resource::server { '10.41.0.1':
     listen_port => 80,
     www_root    => '/usr/share/nginx/html/',