Don't check for negative rc from boolean.

  Don't pointlessly initialize variables, it short-circuits
  gcc's uninitialized variable warnings. And max_new_nr_segs
  can never be zero, so don't check for it.

  Preserve original kstrdup pointer for freeing later.

  Don't check for negative value in unsigned variable.
Signed-off-by: Mike Marshall <hubcap@omnibond.com>