Retry if releasing lock reduced nchunks. (#646)
Always retry the scan after an LSM cursor re-locks the tree.
In lsm_cursor.c, s/skip_chunks/live_chunks/ for clarity.
Switch LSM cursors to using the simplified realloc interface.
Only retry LSM cursor opens if the underlying tree has changed.
Merge pull request #647 from wiredtiger/lsm-retry

Retry if an LSM tree changed while the lock was dropped. (#646)