Fix missing timeout

Seems I screwed up pretty significantly, and this job kept running with
a five-minute timeout. No joy there.

Change-Id: Ieb8a8437fc68d382e5be0878fdb3b6b693743f83
diff --git a/zuul.yaml b/zuul.yaml
index 41598e1..937f8bb 100644
--- a/zuul.yaml
+++ b/zuul.yaml
@@ -10,6 +10,7 @@
       nodes:
         - name: w
           label: f29
+    timeout: 900
 
 - job:
     name: run-ci-build-sh-f31