- strings are now assumed to always be Unicode

This fixes a bug where this caused a crash:

LANG=C bin/logstash agent -e 'filter { mutate { replace => { "message"
=> "☹" } } } output { stdout { codec => json } }'

The problem was that LANG=C told ruby's eval() what the encoding of
strings was by default, and since logstash requires UTF-8/unicode
elswhere, it makes sense to require it for the config file as well.

lib/logstash/config/config_ast.rb

@@ -196,19 +196,26 @@ module LogStash; module Config; module AST
   end
   class RValue < Node; end
   class Value < RValue; end
+
+  module Unicode
+    def self.wrap(text)
+      return "(" + text.inspect + ".force_encoding(\"UTF-8\")" + ")"
+    end
+  end
+
   class Bareword < Value
     def compile
-      return text_value.inspect
+      return Unicode.wrap(text_value)
     end
   end
   class String < Value
     def compile
-      return text_value[1...-1].inspect
+      return Unicode.wrap(text_value[1...-1])
     end
   end
   class RegExp < Value
     def compile
-      return text_value
+      return "Regexp.new(" + Unicode.wrap(text_value[1...-1]) + ")"
     end
   end
   class Number < Value

lib/logstash/outputs/base.rb

@@ -66,6 +66,7 @@ class LogStash::Outputs::Base < LogStash::Plugin
 
     if !@tags.empty?
       return false if !event["tags"]
+      @include_method = :any?
       if !@tags.send(@include_method) {|tag| event["tags"].include?(tag)}
         @logger.debug? and @logger.debug("outputs/#{self.class.name}: Dropping event because tags don't match #{@tags.inspect}", event)
         return false