manager.buildSuccess() doesn't actually set the build result to success

Steps:
1. create freestyle project with one shell step that just does "exit 1"
2. add Groovy Postbuild script that calls "manager.buildSuccess()" per the documentation

Build log result:

Building remotely on vls-linux-1
[f-test] $ /bin/sh -xe /tmp/hudson2407675428334835056.sh
+ exit 1
Build step 'Execute shell' marked build as failure
Build step 'Groovy Postbuild' marked build as failure // THIS SHOULD BE SUCCESS, NO?
Notifying upstream projects of job completion
Finished: FAILURE