docs: Remove build dependency on rsync
docs: Remove build dependency on rsync

We now use `cp` rather than `rsync` to copy the built files.

kklin/kelda,kayousterhout/quilt,ejj/quilt-dev,NetSys/quilt,kklin/quilt,quilt/quilt,kklin/kelda,kelda/kelda,kklin/quilt,ejj/quilt-dev,kklin/kelda,NetSys/quilt,kklin/kelda,ejj/quilt-dev,quilt/quilt,kelda/kelda,NetSys/quilt,kklin/quilt,kklin/quilt,LuiseV/quilt,quilt/quilt,kelda/kelda,LuiseV/quilt,LuiseV/quilt,ejj/quilt-dev,kayousterhout/quilt,kayousterhout/quilt,LuiseV/quilt,NetSys/quilt,LuiseV/quilt,NetSys/quilt,quilt/quilt,kelda/kelda,kayousterhout/quilt