Build Farm temporary name issue

[Green, Paul]

I have commited a change to build_test.fns that should resolve this
issue on VOS, while not messing up any other system.  I'll monitor the
build farm to ensure that's the case.

Thanks
PG
 

A few days ago, I wrote:
> The build farm procedure "s4selftest_update" uses a rather roundabout
> method to copy the directory named "s4selftest" into (e.g.)
> "s4selftest.samba_3_2_test.gcc":
> 
> s4selftest_update() {
>         lock_file "s4selftest.lck" || {
>                 return 1;
>         }
> 
>         copy_dir $s4selftest $s4selftest.$tree.$compiler.$$ || {
>                 rm -rf $s4selftest.$tree.$compiler.$$;
>                 unlock_file "s4selftest.lck";
>                 return 1;
>         }
> 
>         rm -rf $s4selftest.$tree.$compiler
>         mv $s4selftest.$tree.$compiler.$$ $s4selftest.$tree.$compiler
> 
>         unlock_file "s4selftest.lck"
> }
> 
> It first copies the s4selftest subdirectory into a temporary,
> uniquely-named subdirectory, deletes the old target directory, then
> renames the temporary, uniquely-named subdirectory into the 
> final target
> directory.
> 
> This fails on host m104 because the directory name that is 
> generated for
> the temporary directory is too long; while we now support 
> 255-character
> file names, VOS still limits directory names to 32 characters. The
> generated name is 39 characters long.