Revert "epm-addrepo: don't use apt-repo as callback anymore"

bin/epm-addrepo

@@ -385,7 +385,9 @@ __epm_addrepo_altlinux()
         return
     fi
 
-    fatal "Can't recognize how to add $repo, please report it"
+    # TODO: rewrite this fallback
+    assure_exists apt-repo
+    sudocmd apt-repo $dryrun add "$repo"
 }