Also use that profile in create-release.sh

cc pwendell -- Note that this means that we need `knitr` and `roxygen` installed on the machines used for building the release. Let me know if you need help with that.

Author: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Closes #6567 from shivaram/SPARK-8027 and squashes the following commits:

8dc8ecf [Shivaram Venkataraman] Add maven profile to build R package docs Also use that profile in create-release.sh