patch applied (ghc): Changes the behavior of the " edit" command in GHCi.

[Ian Lynagh]

Fri May 25 09:31:04 PDT 2007  iavor.diatchki at gmail.com
  * Changes the behavior of the "edit" command in GHCi.
  Currently, when the user invokes the GHCi editor without a parameter
  GHCi chooses the last file that loaded _sucessfully_.
  This patch changes this behavior to start the editor with the
  last file that _faild_ (this being what I usually want to edit).
  Caveat: we use the module graph to determine what happened
  and so we do not catch errors that occured during dependecy
  analysis (e.g., a mis-typed module name) but we could fix this later.

    M ./compiler/ghci/InteractiveUI.hs -19 +41