bpo-22831: Use "with" to avoid possible fd leaks in tools (part 2). (GH-10927)

diff --git a/Tools/scripts/cleanfuture.py b/Tools/scripts/cleanfuture.py
index b48ab60..94f6912 100755
--- a/Tools/scripts/cleanfuture.py
+++ b/Tools/scripts/cleanfuture.py
@@ -96,11 +96,11 @@
         errprint("%r: I/O Error: %s" % (file, str(msg)))
         return
 
-    ff = FutureFinder(f, file)
-    changed = ff.run()
-    if changed:
-        ff.gettherest()
-    f.close()
+    with f:
+        ff = FutureFinder(f, file)
+        changed = ff.run()
+        if changed:
+            ff.gettherest()
     if changed:
         if verbose:
             print("changed.")
@@ -122,9 +122,8 @@
             os.rename(file, bak)
             if verbose:
                 print("renamed", file, "to", bak)
-            g = open(file, "w")
-            ff.write(g)
-            g.close()
+            with open(file, "w") as g:
+                ff.write(g)
             if verbose:
                 print("wrote new", file)
     else: