exceptions: assume Ruby 2.

Library/Homebrew/exceptions.rb

@@ -350,7 +350,7 @@ class BuildError < RuntimeError
       end
     end
     puts
-    if RUBY_VERSION >= "1.8.7" && issues && !issues.empty?
+    if issues && !issues.empty?
       puts "These open issues may also help:"
       puts issues.map { |i| "#{i["title"]} #{i["html_url"]}" }.join("\n")
     end