[autotest] Let log socket server use an unused port

BUG=chromium:383370
TEST=unittest

Change-Id: I56df36cb230d4f4f81f8ce1525b417a132c15aaf
Reviewed-on: https://chromium-review.googlesource.com/203542
Tested-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Jiaxi Luo <jiaxiluo@chromium.org>
Reviewed-by: Prashanth B <beeps@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
diff --git a/frontend/afe/json_rpc/serviceHandler.py b/frontend/afe/json_rpc/serviceHandler.py
index ede705c..b0d9e84 100644
--- a/frontend/afe/json_rpc/serviceHandler.py
+++ b/frontend/afe/json_rpc/serviceHandler.py
@@ -96,8 +96,8 @@
         timer = stats.Timer('rpc')
 
         try:
-            meth = self.findServiceEndpoint(methName)
             timer.start()
+            meth = self.findServiceEndpoint(methName)
             results['result'] = self.invokeServiceEndpoint(meth, args)
         except Exception, err:
             results['err_traceback'] = traceback.format_exc()