It is possible to get into a situation where a small accumulate operation
can not be completed because a large accumulate operation holds the lock.
In this case we may return from wait/flush/etc before the operation is
complete. To handle this case increment the expected incoming fragment
count when queuing an accumulate operation and increment the incoming
fragment count after processing the accumulate operation.
cmr=v1.8:reviewer=jsquyres
This commit was SVN r31224.
0d703759f6