This is quite unique to maas; as no other software is getting backports with explicit features that enables systemd support on trusty. E.g. cloud-init backports are done in such a way, that when compiled on trusty, no systemd support is installed nor available.
You may want to choose to make init-system selection code innert, as a compile time / dependency option, such that on trusty there is no dynamic selection of things at all.
This is quite unique to maas; as no other software is getting backports with explicit features that enables systemd support on trusty. E.g. cloud-init backports are done in such a way, that when compiled on trusty, no systemd support is installed nor available.
You may want to choose to make init-system selection code innert, as a compile time / dependency option, such that on trusty there is no dynamic selection of things at all.