Adjust use of page cache on new file data based upon size of block cache by vnode
add variable cleanup supplied by maksqwe.  fix sign/unsigned warning.
only force level 0 to page cache.  forcing level 1 is bad in tight memory conditions.
correct if statement to less than or equal after performance verification (hurts 8 vnode a little, helps 64 vnode a little)
Merge pull request #139 from basho/mv-tuning9

Mv tuning9