[tricium] Enable limited Pylint analyzer in to chromium/src

This would enable Pylint with a few warning types in chromium/src.

Change-Id: Ie37d44da7b8256a52f0b9f05a0c517b599b11da3
Reviewed-on: https://chromium-review.googlesource.com/1252201Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Reviewed-by: Erik Staab <estaab@chromium.org>
Commit-Queue: Quinten Yearsley <qyearsley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595221}

infra/config/global/tricium-prod.cfg

@@ -16,6 +16,19 @@ selections {
   platform: UBUNTU
 }
 
+selections {
+  function: "Pylint"
+  platform: UBUNTU
+  configs {
+    name: "disable"
+    value: "all"
+  }
+  configs {
+    name: "enable"
+    value: "syntax-error,unused-variable,undefined-variable,unused-import"
+  }
+}
+
 repos {
   gerrit_project {
     host: "chromium-review.googlesource.com"