libcap-ng: clean-up

component/libcap-ng/buildout.cfg

 [buildout]
-
-extends =
-  ../attr/buildout.cfg
-
 parts = libcap-ng
 
 [libcap-ng]
 recipe = slapos.recipe.cmmi
 shared = true
-url = http://sources.buildroot.net/libcap-ng/libcap-ng-0.8.2.tar.gz
+url = https://people.redhat.com/sgrubb/libcap-ng/libcap-ng-${:version}.tar.gz
+# ERROR: The certificate of 'people.redhat.com' doesn't have a known issuer.
+alternate-url = http://sources.buildroot.net/libcap-ng/libcap-ng-${:version}.tar.gz
+version = 0.8.2
 md5sum = faf1ef766cf068ad1aba4008ced665f7
-location = @@LOCATION@@
 configure-options =
   --with-python=no
   --with-python3=no