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: I4b8f8fc521386419a3121bbb07edc8ac83170a94
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3413679
Reviewed-by: Josip Sokcevic <sokcevic@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.',