fix: Fix removal of entries in account file

Commit 81f92f1fe introduced a selective update mechanism to
_accounts_save() to prevent overwrites when running multiple instances
by only modifying the specific account being saved.

Commit 5c484c fixed a problem with that commit regarding empty accounts.

It turns there was another bug introduced:
The new implementation only set the keys that existed in memory.
So removal of keys was not possible anymore.

Fixes: 81f92f1fed
Ref: 5c484c26ed
Signed-off-by: Michael Vetter <jubalh@iodoru.org>

tests/unittests/ui/stub_ui.c

@@ -62,6 +62,14 @@ ui_init(void)
 {
 }
 void
+ui_suspend(void)
+{
+}
+void
+ui_resume(void)
+{
+}
+void
 ui_load_colours(void)
 {
 }