[MTT users] [BOLO] MTT can abort on "min_disk_free" check

[Ethan Mallove]

I saw this last night in an MTT run:

  Cannot fork Not enough space at .../lib/MTT/Util.pm line 100

Util.pm:

   97         # Setup min_disk_free to be a number of bytes
   98         $df_handle = new Filesys::DiskFree;
   99         if ($MTT::Globals::Values->{min_disk_free} =~ m/([0-9]{1,2})\%/) {
  100             $df_handle->df();
  101             my $val = $1;
  102             $val /= 100.0;
  103             $val *= $df_handle->total(cwd());
  104             $val = int($val);
  105             $MTT::Globals::Values->{min_disk_free} = $val;
  106         }

I've added a Trace line to my MTT client to see if I can
determine how a simple "df" caused a croak.

-Ethan