Disable unused recipe 'collectd_web'

This is a workaround for breaking dbd3027cb837ea04abfe5b410daac742d0a5dfc1 to avoid Chef11 to [raise a CookbookNotFound
exception](http://docs.opscode.com/breaking_changes_chef_11.html#non-recipe-file-evaluation-includes-dependencies) (since no apache2 cookbook is available in travis-cookbooks
repository)

@roidrage do you agree with this trick?