Remove osmium from blacklisted formulas

Library/Homebrew/missing_formula.rb

@@ -64,10 +64,6 @@ module Homebrew
           and then follow the tutorial:
             #{Formatter.url("https://github.com/technomancy/leiningen/blob/stable/doc/TUTORIAL.md")}
           EOS
-        when "osmium" then <<-EOS.undent
-          The creator of Osmium requests that it not be packaged and that people
-          use the GitHub master branch instead.
-          EOS
         when "gfortran" then <<-EOS.undent
           GNU Fortran is now provided as part of GCC, and can be installed with:
             brew install gcc

Library/Homebrew/test/missing_formula_spec.rb

@@ -88,14 +88,6 @@ describe Homebrew::MissingFormula do
       it { is_expected.to be_blacklisted }
     end
 
-    context "osmium" do
-      %w[osmium Osmium].each do |s|
-        subject { s }
-
-        it { is_expected.to be_blacklisted }
-      end
-    end
-
     context "gfortran" do
       subject { "gfortran" }