RUBY-359 Fix for OrderedHash on 1.8.7

lib/bson/ordered_hash.rb

@@ -130,11 +130,12 @@ module BSON
       end
 
       def delete_if(&block)
-        self.each do |k,v|
-          if yield k, v
-            delete(k)
+        keys.each do |key|
+          if yield key, self[key]
+            delete(key)
           end
         end
+        self
       end
 
       def reject(&block)

test/bson/ordered_hash_test.rb

@@ -212,6 +212,8 @@ class OrderedHashTest < Test::Unit::TestCase
     assert @oh.keys.include?('z')
     @oh.delete_if { |k,v| k == 'z' }
     assert !@oh.keys.include?('z')
+    @oh.delete_if { |k, v| v > 0 }
+    assert @oh.keys.empty?
   end
 
   def test_reject