patch applied (packages/HaXml): Fix a space leak in Xtract.

[Malcolm Wallace]

Tue Oct 23 02:07:06 PDT 2007  Malcolm.Wallace at cs.york.ac.uk
  * Fix a space leak in Xtract.
  Do not hold a pointer to the outer document unnecessarily, if the Xtract
  query never uses an absolute path reference.  Relative-only paths are
  pretty common, and fixing the space leak is _very_ important for
  performance on huge documents.

    M ./src/Text/XML/HaXml/Xtract/Combinators.hs -1 +13
    M ./src/Text/XML/HaXml/Xtract/Parse.hs -13 +28