Follow-up for Deb: Stop depending on empty transitional package dh-systemd

058d93d4 introduced a switch in autobake
script to append dh-systemd package when it is necessary. However, the
change was not complete as it didn't actually remove the dh-systemd
dependency in debian/control.

debian/control

@@ -7,7 +7,6 @@ Build-Depends: bison,
                cracklib-runtime <!nocheck>,
                debhelper (>= 9.20160709~),
                dh-exec,
-               dh-systemd,
                flex [amd64],
                gdb <!nocheck>,
                libaio-dev [linux-any],