Regression: descending iterator starts at wrong doc

After updating ForestDB from commit fd41b293 (stable branch 4/23/16) to bc0e6044 (current stable branch), a Couchbase Lite unit test is failing. The test has to do with descending-order iteration starting with a call to fdb_iterator_seek_to_max, where the end_key doesn't exist.

In this test the database contains documents with keys doc-000, doc-001 ... doc-099.

• fdb_iter_init(start_key="doc-024", end_key="doc-029b", opt=0)
• fdb_iter_seek_to_max()
• fdb_iter_get()

Expected: Reads document doc-029
Actual: Reads document doc-030