Ext: problem is with localdepth initialization

-initSize is going to be the number of initial buckets.
-This should be a power of 2.
-mod is initialized to initSize.
-The size of mod is the number of directory slots.
-so at the start, the # of buckets == # of directory slots
Therefore, FOR THE INITIAL BUCKETS we should initialize localDepth = to
global depth.

However, what we CAN'T do is initialize NEW bucket's LD to the global
depth. The formula to initialize the LD is (globaldepth - # of directory
slots pointing to the bucket + 1)
We were only applying this formula to the initial buckets.

initializing localdepth as global depth would cause a lot of directory
doubling.