[one-time-pass] Delete

The script is not useful at all, not very funny, and depneds on
bash features.
Fix various bashisms and small style issues with the scripts

* Fix most of the issues reported by checkbashisms script.  This
  mostly includes use of == instead of = in test.

* When creating temporary files, require mktemp or tempfile.  Do not
  rely on a loop in shell that creates the file.  This bloats the code
  and is not strictly speaking correct.  This change also removes most
  of the use of $RANDOM.

* Drop space in shebang line in SlackBuild.gen file.  “#! /bin/sh”
  being more portable than “#!/bin/sh” is a myth (which I used to
  believe but not any more).

* Drop the use of declare in check.sh.  It was guarded by a check
  whether shell the script is running is bash, but if the code is
  expected to work well w/o declare call, then just never do it.

* Use “#!/bin/sh” in mpd-state-wrapper.sh and traf.sh.  Both of the
  scripts do not depend on any non-POSIX features.