lint: fix a variety of minor warnings w/newer pylint

BUG=chromium:1006448
TEST=CQ passes

Change-Id: Ie51afcefee7508f252c0341ef3da79a45309d328
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2203762
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/sysmon/net_metrics_unittest.py b/scripts/sysmon/net_metrics_unittest.py
index 2489ff3..4d7483a 100644
--- a/scripts/sysmon/net_metrics_unittest.py
+++ b/scripts/sysmon/net_metrics_unittest.py
@@ -58,6 +58,7 @@
       getfqdn.return_value = 'foo.example.com'
       net_if_addrs.return_value = {
           'lo': [
+              # pylint: disable=not-callable
               snic(family=psutil.AF_LINK, address='11:22:33:44:55:66',
                    netmask=None, broadcast=None, ptp=None),
               snic(family=socket.AF_INET, address='10.1.1.1', netmask=None,