[gtk+] treeview: prefer positive polarity in if block

[Cosimo Cecchi <cosimoc src gnome org>]

commit 2eb7e6a85a1a7959c0b26501d8eac5e93ee7eb95
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Tue Dec 29 18:02:21 2015 -0800

    treeview: prefer positive polarity in if block

 gtk/gtktreeview.c |   14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)
---
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index b12fae7..52fd9d2 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -6327,18 +6327,18 @@ validate_row (GtkTreeView *tree_view,
                                          NULL, NULL, NULL,
                                          NULL, &row_height);
 
-      if (!is_separator)
+      if (is_separator)
        {
-          row_height += vertical_separator;
-         height = MAX (height, row_height);
-         height = MAX (height, expander_size);
-       }
-      else
-        {
           if (wide_separators)
             height = separator_height;
           else
             height = 2;
+       }
+      else
+        {
+          row_height += vertical_separator;
+          height = MAX (height, row_height);
+          height = MAX (height, expander_size);
         }
 
       if (gtk_tree_view_is_expander_column (tree_view, column))