chrony: S49chrony: drop /etc/chrony.conf check

chrony: S49chrony: drop /etc/chrony.conf check

With CHRONY_ARGS in /etc/default/chrony, chrony may asked to use an
alternative configuration file (with the -f option), so drop the explicit
/etc/chrony.conf check.

In case the configuration file isn't present chrony will anyway loudly
complain which is preferable to this silent failure:

chronyd -f /non/existing/file.conf
Could not open configuration file /non/existing/file.conf : No such file or directory

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>