SERVER-15905 Ensure Initial Sync uses the same source when fetching oplog and missing docs
Revert "TokuFT: added log flush thread"

This reverts commit 7470b79c2ad68c811d72170cc531c786886f7294.

Conflicts:
	src/mongo/db/storage/tokuft/tokuft_engine.cpp
Merge branch 'master' of https://github.com/mongodb/mongo into tokuft
Fix up a bit more