Generated tarball contains full path where package was built

Checking RC2 I've realized that generated tarball contains full path where package was built.

I.e., assuming you have s2graph source code at /foo/bar, the .tar.gz will inside contain the binary at /foo/bar/target/apache-s2graph-0.1.0-incubating-bin/..., which may not be a good idea when later deploying the binary somewhere else.