e2mmap.rb: suppress a warning

* lib/e2mmap.rb (bind): eval with the location.  undefine
  predefined method before overwriting to suppress a warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56615 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/e2mmap.rb

@@ -62,16 +62,20 @@ module Exception2MessageMapper
   end
 
   def bind(cl)
-    self.module_eval %[
+    self.module_eval "#{<<-"begin;"}\n#{<<-"end;"}", __FILE__, __LINE__+1
+    begin;
       def Raise(err = nil, *rest)
         Exception2MessageMapper.Raise(self.class, err, *rest)
       end
       alias Fail Raise
 
+      class << self
+        undef included
+      end
       def self.included(mod)
         mod.extend Exception2MessageMapper
       end
-    ]
+    end;
   end
 
   # Fail(err, *rest)