daemon-system: Only build on ARCHES_QEMU

The package directly depends on daemon-driver-qemu, so it
would be uninstallable on any other architecture anyway.
Making it not exist at all instead makes for a better user
experience.

debian/control

@@ -814,7 +814,7 @@ Homepage: https://libvirt.org/kbase/locking-sanlock.html
 
 Package: libvirt-daemon-system
 Section: admin
-Architecture: linux-any
+Architecture: amd64 arm64 armel armhf i386 loong64 mips64el mipsel powerpc ppc64 ppc64el riscv64 s390x sparc64 x32
 Depends:
  libvirt-clients (= ${binary:Version}),
  libvirt-common (= ${binary:Version}),

debian/control.in

@@ -706,7 +706,7 @@ Homepage: https://libvirt.org/kbase/locking-sanlock.html
 
 Package: libvirt-daemon-system
 Section: admin
-Architecture: linux-any
+Architecture: ${ARCHES_QEMU}
 Depends:
  libvirt-clients (= ${binary:Version}),
  libvirt-common (= ${binary:Version}),