devserver: turn off auto-reload

Auto-reload brings more confusion than benefits. Turn it off in the
config.

BUG=chromium:368040
TEST=Ran devserver.py and modified the script

Change-Id: I3f19095e34c3561e3e76488555d373f84286c77c
Reviewed-on: https://chromium-review.googlesource.com/197816
Tested-by: Yu-Ju Hong <yjhong@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Yu-Ju Hong <yjhong@chromium.org>
diff --git a/devserver.py b/devserver.py
index 97cbded..b9e0d18 100755
--- a/devserver.py
+++ b/devserver.py
@@ -151,6 +151,7 @@
                     'request.show_tracebacks': True,
                     'server.socket_timeout': 60,
                     'server.thread_pool': 2,
+                    'engine.autoreload.on': False,
                   },
                   '/api':
                   {