Comment 20 for bug 1273462

I think the change description within the patch is wrong (or at least, misleading/incomplete). What this patch actually does is:
 - for anything that calls /etc/init.d/foo, if /etc/init/foo.conf exists, make the call a passthrough to upstart instead of calling the init script.
 - for anything that calls /etc/rc?.d/[KS]??foo, make it a no-op.

The *only* thing that's made a no-op is the invocation of the init script *by the rc?.d symlink*. This is something that should never happen anyway; our dependency-based boot is already supposed to bypass invoking this script in favor of the upstart job. Any system that has been configured to not use the dependency-based boot in trusty is going to have race conditions at boot because of the combination of upstart job and init script, and while making this change may change the characteristics of the behavior at boot it would not be a regression because things are already broken.

If anything interfaces with the /etc/init.d/foo script, that will still function, except that now it will *work* by passing through to the upstart job instead of trying to manipulate processes via (possibly non-existent) pid files etc