rngd failing on certain occasions

[cornelinux]

In certain install scenarios the rngd fails. (No need to discuss if such install variants are sensible or not).

We could modify the postinst (also nginx!?) script like

create_gpg() {
	mkdir -p /etc/privacyidea/gpg
	rngd -r /dev/urandom || logger "Could not start the rng daemon."
	/opt/privacyidea/bin/pi-manage create_pgp_keys || true
	chown -R $USERNAME /etc/privacyidea/gpg
	killall -9 rngd || true
}

[cornelinux]

Please check if we can use std ubuntu install log mechanisms.