patch applied (ghc-6.8/ghc): FIX #2122: file locking bug

[Ian Lynagh]

Tue Feb 26 02:46:50 PST 2008  Simon Marlow <simonmar at microsoft.com>
  * FIX #2122: file locking bug
  Second and subsequent readers weren't being inserted into the
  fd->lock hash table, which meant that the file wasn't correctly
  unlocked when the Handles were closed.

    M ./rts/posix/FileLock.c +1