Comment 13 for bug 1310082

This patch to the preseed should fix it

=== modified file 'contrib/preseeds_v2/generic'
--- contrib/preseeds_v2/generic 2014-04-14 22:40:43 +0000
+++ contrib/preseeds_v2/generic 2014-07-04 00:21:11 +0000
@@ -2,7 +2,7 @@

 {{def proxy}}
 d-i mirror/country string manual
-{{if node.architecture in {'i386/generic', 'amd64/generic'} }}
+{{if node.split_arch()[0] in {'i386', 'amd64'} }}
 d-i mirror/http/hostname string {{main_archive_hostname}}
 d-i mirror/http/directory string {{main_archive_directory}}
 {{else}}