llgoi: Fix importing source packages together with dependent binary packages.

Note that this means that llgoi does not support the case
where a package's pkgpath is different from its import path,
but I don't think this should actually happen with llgoi.

Differential Revision: http://reviews.llvm.org/D8403

llvm-svn: 232612
GitOrigin-RevId: 6092d2c06540c83b3e261835d045822af1ea9e2f
4 files changed