Fix wrong locked sibling check

Previously if the split type was "hsplit", but `locked_size_x` was 
falsy, `locked_size_y` was wrongly used.

data/core/rootview.lua

@@ -143,8 +143,13 @@ function Node:remove_view(root, view)
     local is_a = (parent.a == self)
     local other = parent[is_a and "b" or "a"]
     local locked_size_x, locked_size_y = other:get_locked_size()
-    if self.is_primary_node
-       or (parent.type == "hsplit" and locked_size_x or locked_size_y) then
+    local locked_size
+    if parent.type == "hsplit" then
+      locked_size = locked_size_x
+    else
+      locked_size = locked_size_y
+    end
+    if self.is_primary_node or locked_size then
       self.views = {}
       self:add_view(EmptyView())
     else