Add dependency type tp r- packages

This PR adds the `nolink` dependency type to r- package dependencies.
This is needed due to the new dependency types in Spack. A couple of
packages were updated with new versions as well.

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

@@ -42,7 +42,7 @@ class RHttpuv(Package):
 
     extends('R')
 
-    depends_on('r-rcpp')
+    depends_on('r-rcpp', type=nolink)
 
     def install(self, spec, prefix):
         R('CMD', 'INSTALL', '--library={0}'.format(self.module.r_lib_dir),