Use custom alternative to __method__ if we're using 1.8.7 or above, not just above 1.8.7.

lib/aws/s3/extensions.rb

@@ -134,7 +134,7 @@ module Kernel
   end if RUBY_VERSION > '1.8.7'
   
   def expirable_memoize(reload = false, storage = nil)
-    current_method = RUBY_VERSION >= '1.8.7' ? __called_from__ : __method__(1)
+    current_method = RUBY_VERSION > '1.8.7' ? __called_from__ : __method__(1)
     storage = "@#{storage || current_method}"
     if reload 
       instance_variable_set(storage, nil)