Revert "mogwai-scheduled: Fix dependency name for systemd"

This reverts commit ed84c697, and additionally changes the CI config to install the package providing systemd.pc, which was missing before. libsystemd-dev needs to be kept as a dependency, as libsystemd.so is actually used by the libgsystemservice subproject. The CI build uses libgsystemservice as a subproject as it’s not available on Debian Unstable at the moment.

The pkg-config name was correct before. Both libsystemd.pc and systemd.pc exist, but systemd.pc is the one which defines all systemd’s directory paths and variables. libsystemd.pc is just for the cflags/libs for linking to libsystemd.

Unsure how I managed to get this commit working before.

Signed-off-by: Philip Withnall pwithnall@endlessos.org