Smarter default rockspec, based on current dir basename
Smarter default rockspec, based on current dir basename

This allows the following to work:

```
git clone https://github.com/example/foo
cd foo
luarocks download --rockspec bar
luarocks test # will still use the foo rockspec
              # regardless of the presence of bar rockspec
```

tarantool/luarocks,luarocks/luarocks,keplerproject/luarocks,keplerproject/luarocks,keplerproject/luarocks,luarocks/luarocks,tarantool/luarocks,luarocks/luarocks,tarantool/luarocks,keplerproject/luarocks