Open LogView in correct Node

Using `get_active_node` might result in a locked `Node`; calling 
`add_view` on that `Node` throws an error.

`get_active_node_default` always returns an unlocked `Node`.

data/core/commands/core.lua

@@ -149,7 +149,7 @@ command.add(nil, {
   end,
 
   ["core:open-log"] = function()
-    local node = core.root_view:get_active_node()
+    local node = core.root_view:get_active_node_default()
     node:add_view(LogView())
   end,