Use improved update-notify script also in Fedora

Among other things this also fixes build failure - those scripts were
installed but not listed in spec file.

Actual check doesn't perform 'apt-get update', so do that when running
"standalone" (not as a hook from 'apt-get').

QubesOS/qubes-issues#1066

rpm_spec/core-vm.spec

@@ -377,6 +377,8 @@ rm -f %{name}-%{version}
 /usr/lib/qubes/close-window
 /usr/lib/qubes/xdg-icon
 /usr/lib/qubes/update-proxy-configs
+/usr/lib/qubes/upgrades-installed-check
+/usr/lib/qubes/upgrades-status-notify
 /usr/lib/yum-plugins/yum-qubes-hooks.py*
 /usr/lib/python2.7/site-packages/dnf-plugins/qubes-hooks.py*
 /usr/lib/dracut/dracut.conf.d/30-qubes.conf

vm-systemd/qubes-update-check.service

@@ -5,4 +5,5 @@ After=qubes-qrexec-agent.service
 
 [Service]
 Type=oneshot
-ExecStart=/usr/lib/qubes/qrexec-client-vm dom0 qubes.NotifyUpdates /bin/sh -c 'if [ -e /etc/system-release ]; then yum -q check-update >/dev/null; [ $? -eq 100 ] && echo 1 || echo 0; else apt-get -q update > /dev/null; apt-get -s upgrade | awk "/^Inst/{ print $2 }" | [ $(wc -L) -eq 0 ] && echo 0 || echo 1; fi'
+ExecStart=/bin/sh -c 'if [ -e /etc/debian_version ]; then apt-get -q update; fi'
+ExecStart=/usr/lib/qubes/upgrades-status-notify