Bug in changes-file copy during smalltalk save.

[Michael McClary <michael>]

Volume full during the copying of the changes file when the saved
image name has been changed does not recover gracefully.

 - The new changes file is still held open, and cannot be
   discarded by switching to finder and dragging to trash.

 - If a new save is attempted, smalltalk presents the new, not
   the old, image name.  (From this I infer that smalltalk thinks
   the save was successful, and would copy from the missing or
   partial files if the new save were allowed to proceed.)

	michael