Delete the files present in the locations $WL_DOMAIN/servers/
Restart the OIF managed servers. Access the OIF application and observe the changes. It has not reflected in my case. I spent a lot of time figuring out the locations where oif.ear is present and making sure whether changes are reflected. Finally I identified that WebLogic staging directory is where the OIF application is moved to and is holding old oif.ear.
So I copied the oif.ear to staging directories of all OIF instances and removed the files under $WL_DOMAIN/servers/