Ensure directories have trailing slashes in doLookupId()

Ensure directories have trailing slashes in doLookupId()

- In the old days, stripping trailing slashes made sense as its useless
  as it is and stripping it saved a bit of memory, but now with the
  directories in the pool things are different: while not all paths
  we'll see here necessarily exist in the pool already, NONE of them
  exists without the trailing slash, so stripping it out wastes gobs
  of memory.  Simplifies the code a bit and saves several megs of memory
  on larger transactions, what's not to like?