Use the latest HEAD for server-syncstorage and tokenserver dependencies.

If this helps get folks back up and running with the latest syncserver
docker image, we can tag some new releases of both and then reference
them here, but let's try it out first.

requirements.txt

@@ -12,5 +12,5 @@ futures==3.0
 soupsieve==1.9.5
 umemcache==1.6.3
 google-cloud-spanner==1.18.0
-https://github.com/mozilla-services/tokenserver/archive/1.5.11.zip
-https://github.com/mozilla-services/server-syncstorage/archive/1.8.0.zip
+https://github.com/mozilla-services/tokenserver/archive/bf5f232ed78fb4eb89909ec5be40f135945aa514.zip
+https://github.com/mozilla-services/server-syncstorage/archive/d370a488155adeb80ee6f1bc016a4aa9d009f181.zip