[t:3674] #3674 Simplify and fix workdone accounting. Also delete useless...

[t:3674] #3674 Simplify and fix workdone accounting.  Also delete useless is_root argument from function apply_cmd_to_in_memory_non_root_leaves().

git-svn-id: file:///svn/toku/tokudb@32775 c7de825b-a66e-492c-adef-691d508d4ae1