Merge doesn't need to clear pages from the eviction queue or clear the eviction position: we're using the same locking scheme as normal eviction.
We have to remove live pages from the LRU queue during merge: we check before evicting that page == page->ref->page, which merge violates briefly.
Merge branch 'develop' into merge-no-clear
Merge pull request #529 from wiredtiger/merge-no-clear

Merge doesn't need to clear pages from the eviction queue or clear the eviction position