redo-ifchange.py: don't forget to release jwack tokens on exit.

This only really matters if it exited abnormally... but it still matters.

redo-ifchange.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python
 import sys, os, errno
-import vars, state, builder
+import vars, state, builder, jwack
 from helpers import debug, err, mkdirp, unlink
 
 
@@ -56,6 +56,7 @@ if not vars.TARGET:
 
 rv = 202
 try:
+    try:
         want_build = []
         for t in sys.argv[1:]:
             state.add_dep(vars.TARGET, 'm', t)
@@ -63,6 +64,8 @@ try:
                 want_build.append(t)
 
         rv = builder.main(want_build, maybe_build)
+    finally:
+        jwack.force_return_tokens()
 except KeyboardInterrupt:
     sys.exit(200)
 sys.exit(rv)