AppRunner: Include commit hash in the ping request

Increase ping frequencey to twice a second.

Change-Id: I43a064d17a22525e276140c689bea23df6c31655
diff --git a/apps/app-runner/log.go b/apps/app-runner/log.go
index 084e3d1..f04760e 100644
--- a/apps/app-runner/log.go
+++ b/apps/app-runner/log.go
@@ -49,6 +49,7 @@
 			l.items = append(l.items, l.curr)
 			l.curr = LogItem{
 				RunId:    l.runId,
+				Commit:   l.commitHash,
 				Contents: []byte{},
 			}
 			p = p[pos+len([]byte("\n")):]