Ensure multi-item chunks in couch_btree:chunkify/1

If the last element of a chunk has a huge reduction it was possible to
return a btree node that had a single key. This prevents the edge case
by forcing it into the previous chunk. Without this we can end up with a
case where a path in the tree can extend for many levels with only a
single key in each node.

COUCHDB-3298
1 file changed
tree: fbdbf36bc3cf0a23abb77ceaf47fedada3362489
  1. include/
  2. priv/
  3. src/
  4. test/
  5. .gitignore
  6. .travis.yml
  7. LICENSE
  8. rebar.config.script