bin: make running aup in the autoproj root the equivalent of aup --all

This is really what people expect. The big difference is that aup --all
will update the osdeps while aup . would not.
Merge pull request #13 from rock-core/make_aup_in_root_equivalent_of_aup_all

bin: make running aup in the autoproj root the equivalent of aup --all