minimal/do: work around a bug with empty .do files.
minimal/do: work around a bug with empty .do files.

If you ". ./filename" and ./filename contains no commands, apparently
ash/dash will give the exit code of the command *before* the ., rather than
defaulting to zero as it supposedly should.  This should work around it in
our .do files at least.

Reported by Tim Allen.

rowhit/redo,rowhit/redo,dinkelk/redo-python,dinkelk/redo-python,dinkelk/redo-python,pombredanne/redo,apenwarr/redo,pombredanne/redo,apenwarr/redo,rowhit/redo,apenwarr/redo,pombredanne/redo,apenwarr/redo,dinkelk/redo-python,rowhit/redo,pombredanne/redo