Scheduler: free unneeded uninstall task from mem
diff --git a/pym/_emerge/Scheduler.py b/pym/_emerge/Scheduler.py
index eb70e80..f637dd0 100644
--- a/pym/_emerge/Scheduler.py
+++ b/pym/_emerge/Scheduler.py
@@ -1410,7 +1410,11 @@
 		if pkg_to_replace is not None:
 			# When a package is replaced, mark it's uninstall
 			# task complete (if any).
-			self._task_complete(pkg_to_replace)
+			if self._digraph is not None and \
+				pkg_to_replace in self._digraph:
+				self._task_complete(pkg_to_replace)
+			else:
+				self._pkg_cache.pop(pkg_to_replace, None)
 
 		if pkg.installed:
 			return