Add missing clean_up step for the OSI module.

Now the OSI module's shut_down processing is split into "shut_down"
and "clean_up".

Previously, there was an ordering issue manipulating some of the
internal state during graceful shutdown/cleanup. Some of the modules
had two steps: shut_down, followed by clean_up, while other had only
shut_down step. This triggered the following assert in file alarm.c

    alarm_cancel: assertion "alarms != NULL" failed

Bug: 21406940
Change-Id: Iab1f033a69cbff646a6b0f346760ae82f8b00b8f