added missing ] to ip cmd syntax
        - assert writable dirs in _run_mime_helper while disassembling jail.
	  needed for ksh/ast-base.2012-08-01.tar.bz2/src/cmd/pax/data/ro.dat
	- all rename()s in _run_mime_helper() equipped with or die.
	- DESTROY() now handles more cases: Adding the epilog when missing is paramount.