Remove redundant to_sym call.

[#6483 state:committed]

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>

activesupport/lib/active_support/ordered_options.rb

@@ -31,7 +31,7 @@ module ActiveSupport #:nodoc:
 
     def method_missing(name, *args)
       if name.to_s =~ /(.*)=$/
-        self[$1.to_sym] = args.first
+        self[$1] = args.first
       else
         self[name]
       end