[dconf-editor] Restore “Erase key” menu action.

[Arnaud Bonatti <arnaudb src gnome org>]

commit 4e153b280238007ecb757cb8daa211586d001d08
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Wed Jan 10 00:31:23 2018 +0100

    Restore “Erase key” menu action.

 editor/key-list-box-row.vala |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/editor/key-list-box-row.vala b/editor/key-list-box-row.vala
index baef1c0..8638c2c 100644
--- a/editor/key-list-box-row.vala
+++ b/editor/key-list-box-row.vala
@@ -405,7 +405,8 @@ private class KeyListBoxRowEditableNoSchema : KeyListBoxRow
                         change_dismissed ();
                     });
             }
-            else if (planned_value != null)
+
+            if (!planned_change || planned_value != null) // not &&
             {
                 popover.new_section ();
                 popover.new_action ("erase", () => {