hooks: add more net-misc/chrony to the /var exception

BUG=b:150599453
TEST=CQ passes

Change-Id: I5d7ff03fc4611d34799292820d74b255adeda7d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2083162
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Nicolas Norvez <norvez@chromium.org>
diff --git a/hooks/filesystem-sanity.py b/hooks/filesystem-sanity.py
index 9c23ef5..ce666d4 100755
--- a/hooks/filesystem-sanity.py
+++ b/hooks/filesystem-sanity.py
@@ -109,6 +109,7 @@
     'net-dns/dnsmasq',
     'net-firewall/iptables',
     'net-fs/samba',
+    'net-misc/chrony',
     'net-misc/dhcpcd',
     'net-misc/openssh',
     'net-print/cups',