Heads up: objdir is now rm -rf resistent

[Andreas Gustafsson <gson%gson.org@localhost>]

All,

The TNF testbed is currently failing to start new builds because it is
unable to remove the objdirs from previous builds using the Python
equivalent of "rm -rf".

Specifically, after the i386 build fails the way it currently does,
the objdir contains two directories with mode 0111, which rm -rf is
unable to remove:

  obj/distrib/i386/cdroms/bootcd/cdrom/var/spool/ftp/hidden
  obj/distrib/i386/cdroms/bootcd-com/cdrom/var/spool/ftp/hidden

The work-around is to manually chmod the directories to 0755 before
removing the objdir, but until I get around to automating that on the
testbed, you can expect a reduced level of automated testing service.
Also, you may want to be on the lookout for this failure mode in your
own builds (or the cleanup after them).
-- 
Andreas Gustafsson, gson%gson.org@localhost