Replace custom strip newlines in UUID generation

Since now rStripSpace lives in Utils.hs, we can use it directly (as
UUIDs shouldn't contain spaces anyway).

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michele Tartara <mtartara@google.com>

htools/Ganeti/Utils.hs

@@ -285,5 +285,4 @@ rStripSpace = reverse . dropWhile isSpace . reverse
 newUUID :: IO String
 newUUID = do
   contents <- readFile C.randomUuidFile
-  let stripNewlines = reverse . dropWhile (=='\n') . reverse
-  return $! stripNewlines $ take 128 contents
+  return $! rStripSpace $ take 128 contents