The AREASTACK, LINESTACK and LINE[n]STACK were omitted in the previous commit. Add them now.
2.0 master has a bug that makes a field named "root" not allowed anymore. This commit is a workaround in order for these graphs to be displayed again. Proper resolution is due in master, not in the plugins. But patch is much more invasive. So delaying it to 2.1.
…mmend munin-plugins-extra. (Closes: #677189)