Fix rpath-link handling

Summary:
After r333596, rpath-link no longer consumes the following argument, and
the path argument left by it confuses LLD.

Reviewers: espindola, ruiu

Reviewed By: ruiu

Subscribers: ruiu, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D47591

llvm-svn: 333686