Fix changes in 2011-05-01T00:04:17Z!larsi@gnus.org for MS-DOS.

Fix changes in 2011-05-01T00:04:17Z!larsi@gnus.org for MS-DOS.

 src/callproc.c (call_process_cleanup): Don't close and unlink the
 temporary file if Fcall_process didn't create it in the first
 place.
 (Fcall_process): Don't create tempfile if stdout of the child
 process will be redirected to a file specified with `:file'.
 Don't try to re-open tempfile in that case, and set fd[0] to -1 as
 cue to call_process_cleanup not to close that handle.