vchoi_fork

[svn-r13477] Description:
		The main purpose of this checkin was to eliminate the
space used for tracking creation time indices when there is no way they
can be used (i.e. attributes can't be shared in the file and the user hasn't
turned on attribute creation tracking), however there were some other minor
changes which crept in:
	- Fix a cache locking deadlock when a shared attribute and one of its
		components end up in the same fractal heap direct block.  
		(This is fixed the "slow" way for right now, until John has time
		to add support for readers/writer locking to the cache.
	- Optimize attribute copying when a copy will be kept during a v2 B-tree
		search.
	- When freeing a block on disk, attempt to merge it with the metadata
		and "small data" aggregators.

Tested on:
	Mac OS X/32 10.4.8 (amazon)
	FreeBSD/32 6.2 (duty)