Remove unused and obsolete function

The Node.str function is very old and is not useful since the node
objects have much more fields today. This patch removes it, and if
needed a full node display can be done via ‘show’.

Ganeti/HTools/Node.hs

@@ -201,15 +201,6 @@ setPri t idx = t { plist = idx:(plist t) }
 setSec :: Node -> Int -> Node
 setSec t idx = t { slist = idx:(slist t) }
 
--- | Simple converter to string.
-str :: Node -> String
-str t =
-    printf ("Node %d (mem=%5d MiB, disk=%5.2f GiB)\n  Primaries:" ++
-            " %s\nSecondaries: %s")
-      (idx t) (f_mem t) ((f_dsk t) `div` 1024)
-      (commaJoin (map show (plist t)))
-      (commaJoin (map show (slist t)))
-
 -- | String converter for the node list functionality.
 list :: Int -> String -> Node -> String
 list mname n t =