Use pylint 2.7 for depot_tools

This includes a few fixes for specific errors, and disables several new
warnings introduced in this version, in order to allow for an incremental migration.

Bug:1262286
Change-Id: Ie97d686748c9c952e87718a65f401c5f6f80a5c9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3400616
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Aravind Vasudevan <aravindvasudev@google.com>
diff --git a/metrics_utils.py b/metrics_utils.py
index 7097857..96982a9 100644
--- a/metrics_utils.py
+++ b/metrics_utils.py
@@ -54,7 +54,8 @@
 def get_change_notice(version):
   if version == 0:
     return [] # No changes for version 0
-  elif version == 1:
+
+  if version == 1:
     return [
       'We want to collect the Git version.',
       'We want to collect information about the HTTP',
@@ -64,7 +65,8 @@
       'We only collect known strings to make sure we',
       'don\'t record PII.',
     ]
-  elif version == 2:
+
+  if version == 2:
     return [
       'We will start collecting metrics from bots.',
       'There are no changes for developers.',