Fix --with-systemd on Debian-based distributions (#6963)
These changes propagate the "--with-systemd" configure option to the
RPM spec file, allowing Debian-based distributions to package
systemd-related files.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6591
Closes #6963