Fix the class_reset command

The class_reset command used to reset services that had been set to
"disabled" in the init.rc file to a non-disabled state.  Now, if the
service was originally set to "disabled", have the reset command set
it back to disabled.  Otherwise, set it to the "reset" state as it
currently does.

Change-Id: I0c10582e46a8e443d4748d9d893ae762b19b653a