as found necessary during the release build of 5.5.3-m3.

scripts/CMakeLists.txt:
  The scripts "mysqldumpslow" and "mysqlhotcopy" need to be handled.
scripts/make_win_bin_dist:
  1) We do not create ".map" files any more.
  
  2) Typing error fixed, it isn't "$DISTDIR" but "$DESTDIR".
  
  3) Security fix:
     If the argument isn't of the form "dst=src",
     then we want the variables to be empty.
  The original code would have used an argument "foo"
  to set both "$src" and "$dst" to this string,
  which doesn't make much sense.