Use ERESOURCE instead of spinlock to protect the hive list.

Use ERESOURCE instead of spinlock to protect the hive list.
Use worker thread to run hive flush routine at dispatch level.
 - Changes by Hartmut Birr!

Delete a key's hash block when the key is deleted.
Update pointers and offsets in a key object when the key cell is deleted.

svn path=/trunk/; revision=4134