Remove fallback from nb to no

Now that we are using nb for our translations we can drop the fallback
from nb to no and just have one the other way. This also allows us to
drop the monkey patch to support mutually recursive fallbacks.

config/initializers/i18n.rb

@@ -16,20 +16,6 @@ module I18n
       end
     end
   end
-
-  module Locale
-    class Fallbacks
-      def compute(tags, include_defaults = true, exclude = [])
-        result = Array(tags).collect do |tag|
-          tags = I18n::Locale::Tag.tag(tag).self_and_parents.map! { |t| t.to_sym } - exclude
-          tags.each { |_tag| tags += compute(@map[_tag], false, exclude + tags) if @map[_tag] }
-          tags
-        end.flatten
-        result.push(*defaults) if include_defaults
-        result.uniq.compact
-      end
-    end
-  end
 end
 
 I18n::Backend::Simple.include(I18n::Backend::Pluralization)
@@ -38,7 +24,6 @@ I18n.load_path << "#{Rails.root}/config/pluralizers.rb"
 
 I18n::Backend::Simple.include(I18n::Backend::Fallbacks)
 
-I18n.fallbacks.map("nb" => "no")
 I18n.fallbacks.map("no" => "nb")
 
 Rails.configuration.after_initialize do

config/locales/no.yml

@@ -1,2 +0,0 @@
-no:
-  dummy: dummy