Re-add list_url for all R packages (#6110)

* r-igraph: find old packages in the archive

Fixes #6104.

* r-irlba: find old packages in the archive

Fixes #6101.

* r-lazyeval: find old packages in the archive

Fixes #6102.

* packages: set list_url for all packages hosted on CRAN

* packages: consistently use the CRAN archive URLs

var/spack/repos/builtin/packages/r-ade4/package.py

@@ -31,6 +31,7 @@ class RAde4(RPackage):
 
     homepage = "http://pbil.univ-lyon1.fr/ADE-4"
     url      = "https://cran.r-project.org/src/contrib/ade4_1.7-6.tar.gz"
+    list_url = "https://cran.r-project.org/src/contrib/Archive/ade4"
 
     version('1.7-6', '63401ca369677538c96c3d7b75b3f4a1')