[FIX] runbot_merge: sentry issue via monkeypatch

`auto_session_tracking` causes issues when not specified on the super
old version of the client which is available on ubuntu.

Also disable tracing as it seems less useful than hoped for, and I've
not been using what's been collected so far.

runbot_merge/sentry.py

@@ -35,7 +35,8 @@ def enable_sentry():
 def setup_sentry(dsn):
     sentry_sdk.init(
         dsn,
-        traces_sample_rate=1.0,
+        auto_session_tracking=False,
+        # traces_sample_rate=1.0,
         integrations=[
             # note: if the colorformatter is enabled, sentry gets lost
             # and classifies everything as errors because it fails to