give packages a 'url'

There's nothing to download at these URLS yet (no formal releases) but
the spack tools sometimes balk at packages without a 'url'.

packages/argobots/package.py

@@ -29,6 +29,7 @@ class Argobots(AutotoolsPackage):
     """A Lightweight Low-level Threading/Tasking Framework"""
 
     homepage = "http://www.argobots.org/"
+    url = "http://www.argobots.org/"
 
     version('master', git='https://github.com/pmodels/argobots.git');
     version('dev-get-dev-basic', git='https://github.com/carns/argobots.git', branch='dev-get-dev-basic')

packages/sdskeyval/package.py

@@ -29,6 +29,7 @@ class Sdskeyval(AutotoolsPackage):
     """a library that provides a Margo-based keyval service"""
 
     homepage = "https://xgitlab.cels.anl.gov/sds/sds-keyval"
+    url = "https://xgitlab.cels.anl.gov/sds/sds-keyval"
 
     version('master', git='https://xgitlab.cels.anl.gov/sds/sds-keyval.git')