Pull R list_urls from upstream.

var/spack/repos/builtin/packages/r-dbi/package.py

var/spack/repos/builtin/packages/r-dorng/package.py

var/spack/repos/builtin/packages/r-downloader/package.py

var/spack/repos/builtin/packages/r-dplyr/package.py

var/spack/repos/builtin/packages/r-futile-logger/package.py

var/spack/repos/builtin/packages/r-getoptlong/package.py

var/spack/repos/builtin/packages/r-ggvis/package.py

var/spack/repos/builtin/packages/r-glmnet/package.py

var/spack/repos/builtin/packages/r-hms/package.py

var/spack/repos/builtin/packages/r-htmltools/package.py

var/spack/repos/builtin/packages/r-httpuv/package.py

var/spack/repos/builtin/packages/r-hwriter/package.py

var/spack/repos/builtin/packages/r-jsonlite/package.py

var/spack/repos/builtin/packages/r-lattice/package.py

var/spack/repos/builtin/packages/r-locfit/package.py

var/spack/repos/builtin/packages/r-matrix/package.py

var/spack/repos/builtin/packages/r-matrixstats/package.py

var/spack/repos/builtin/packages/r-memoise/package.py

var/spack/repos/builtin/packages/r-mpm/package.py

var/spack/repos/builtin/packages/r-nor1mix/package.py