[t:4838] the locktree now opens its own ft handle when created to ensure that the ft stays in memory so long as the lock tree is in memory. we use an on_create and on_destroy callback to keep the txn/ft logic out of the locktree. the api for toku_ltm_get_lt is a little hairy now. a better solution may come in the future. for now, the original failing test passes.


git-svn-id: file:///svn/toku/tokudb@44819 c7de825b-a66e-492c-adef-691d508d4ae1