Merge rust-lang#19

19: Required  to build in docker due to buildbot change. r=ltratt a=vext01



Co-authored-by: Edd Barrett <vext01@gmail.com>

Author: bors[bot]

bors.toml

@@ -1,5 +1,5 @@
 # The service providing the commit statuses to GitHub.
-status = ["buildbot/yk-buildbot-build-script-hw"]
+status = ["buildbot/buildbot-build-script"]
 
 # Allow four hours for builds + tests.
 timeout_sec = 14400