I don't see any reason the checkpointing field needs to be declared
volatile.
Minor code shuffle, don't free the multiblock structure while our caller
might reasonably still be using it.
Merge pull request #915 from wiredtiger/checkpointing_not_volatile

Remove volatile declaration from checkpointing field.
Merge branch 'develop' into new-split
Merge branch 'new-split' into new-split-overflow