Milo: Handle missing / transient LogDog failures.

milo/appengine/swarming/testdata/build-pending-logdog.swarm

Index: milo/appengine/swarming/testdata/build-pending-logdog.swarm
diff --git a/milo/appengine/swarming/testdata/build-pending-logdog.swarm b/milo/appengine/swarming/testdata/build-pending-logdog.swarm
new file mode 100644
index 0000000000000000000000000000000000000000..834a96821a19b16a2b93de31231353c5ab3ae6e8
--- /dev/null
+++ b/milo/appengine/swarming/testdata/build-pending-logdog.swarm
@@ -0,0 +1,21 @@
+{
+ "created_ts": "2016-06-28T21:19:45.146360",
+ "name": "cipd test",
+ "task_id": "2fb1b35e1da25710",
+ "tags": [
+  "os:Linux",
+  "pool:default",
+  "priority:10",
+  "user:",
+  "allow_milo:1",
+  "luci_project:testproject",
+  "log_location:logdog://example.com/testproject/${swarming_run_id}/+/annotations"
+ ],
+ "internal_failure": false,
+ "failure": false,
+ "state": "PENDING",
+ "modified_ts": "2016-06-28T21:19:45.496930",
+ "user": "",
+ "kind": "swarming#taskItem",
+ "etag": "\"gaJHHV0EOm6X5R9LefcQ1Vn0P2k/s3rYAHDh9d3OTM4C8T8is7hT9Q0\""
+}