debian: Ignore systemd-service-file-missing-install-key lintian info

This is working as intended, only cockpit.socket is supposed to have an
[Install] section.

tools/debian/cockpit-tests.lintian-overrides

@@ -1 +1,3 @@
 cockpit-tests: package-contains-documentation-outside-usr-share-doc *usr/share/cockpit/*html*
+# triggered on demand by cockpit.service
+cockpit-tests: systemd-service-file-missing-documentation-key *[email protected]*

tools/debian/cockpit-ws.lintian-overrides

@@ -4,3 +4,7 @@ cockpit-ws: font-outside-font-dir *usr/share/cockpit/static/fonts/*
 cockpit-ws: font-in-non-font-package *usr/share/cockpit/static/fonts/*
 cockpit-ws: groff-message *macro *an-trap*usr/share/man/man8/cockpit-ws.8.gz*
 cockpit-ws: package-contains-documentation-outside-usr-share-doc *usr/share/cockpit/*html*
+# triggered on demand by cockpit.service
+cockpit-ws: systemd-service-file-missing-install-key *cockpit-wsinstance*
+# triggered by cockpit.socket
+cockpit-ws: systemd-service-file-missing-install-key *cockpit.service*